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FUCK    THE    OPTOMETIIIC    LltKAOY 

MONROE    JEROME    HIRSCH 


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THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 


(;i\T.N  Wnil   I.OVK   TO  THE 

OPTOMETRY   LIBRARY 

BY 

MONROE  ].  HIRSCH,  O.D.,  Ph.D. 


Optometrical  Courses  of  Study 

Ocular 
Accommodation 

by 
Charles  Sheard,  A.  B.,  A.  M.,  Ph.  D. 


Issued  by 

Department  of  Education 

American  Optometric    Association 

Box  1042,  Hartford,  Conn. 

Tf'!jurn'\nYnFTHE 
Ofl  AKGEii  a  «n'i-«L  or  optometry 

il:in  w.  j;:i n:nfin\  nun. 

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OPTcr.-:~TRV 

BIOGRAPHJCAL   SKETCH 
Charles  Sheard,  A.  B.,  A.  M.,  Ph,  D. 

Charles  Sheard  was  born  in  Dolgeville,  New  York,  May  27th,  1883,  and  was 
the  first  born  of  the  Rev.  Dr.  Charles  and  Frances  Emily  Sheard.  During 
his  boyhood  days  he  lived  in  Richfield  Springs,  Cape  Vincent  and  Clayton, 
in  the  State  of  New  York.  His  elementary  education  was  finished  in  the 
schools  of  Canton,  New  York;  in  1899  he  was  graduated  from  the  Canton 
High  School.  He  received  the  baccalaureate  degrees  from  St.  Lawrence 
University  in  1903.  .After  teaching  in  the  public  schools  for  two  years,  he 
entered  Dartmouth  College  as  an  assistant  in  physics,  where  he  remained  until 
1907,  receiving  at  that  time  the  master  of  arts  degree.  In  the  fall  of  that  year 
he  was  appointed  an  instructor  in  physics  at  the  Ohio  State  University  and 
in  1910  was  appointed  assistant  professor  in  the  same  institution.  The  year 
191 2  was  spent  at  Princeton  University,  from  which  institution  he  was  sent 
out  with  the  highest  scholastic  degree  granted  by  universities,  the  degree  of 
doctor  of  philosophy,  having  presented  original  theses  along  the  modern  elec- 
tronic theory  of  matter. 

In  1914  he  played  an  important  part  in  the  establishment  of  the  work  in 
Applied  Optics  at  the  Ohio  State  University  and  became  in  that  year  the 
first  director  and  professor  of  .Applied  Optics.  These  years  spent  at  the  Ohio 
University  were  productive  of  much  research  work  and  many  a  page  of  writing. 
The  period  of  the  world  war  found  him  physically  incapacitated  but  he  served 
in  a  civilian  capacity  in  optical  work  as  well  as  carrying  out  his  duties  as  an 
instructor  and  as  a  clinician  at  the  University. 

In  1919  the  subject  of  this  sketch  became  a  member  of  the  Research  Division 
of  the  American  Optical  Company,  filling  the  newly  created  position  of 
Physiological  Opticist.  In  this  field  of  labor  his  time  is  wholly  spent,  both  in 
writing  and  in  experimental  work. 

His  published  volumes,  some  of  which  are  now  out  of  print  but  which 
are  now  in  the  process  of  being  re-written,  include  a  treatise  of  over  five 
hundred  pages  on  Physiological  Optics,  which  first  appeared  as  a  portion  of 
the  thirteenth  volume  of  the  American  Encyclopedia  of  Ophthalmology  in  1919, 
a  brochure  on  Dynamic  Ocular  Tests  in  1917  and  within  the  past  few  months  a 
volume  entitled  Dynamic  Skiametry  and  other  Methods  of  Testing  Accommo- 
dation and  Convergence.  .Amongst  the  chief  of  his  papers  along  visual  optical 
lines  have  been  a  series  of  articles  on  Mathematical  Studies  in  Optics  and  a 
later  group  of  papers  treating  upon  Accommodation  and  included  under  the 
general  heading  of  Dynamic  Skiametry.  His  researches  have  carried  him  into 
the  fields  of  the  electron  theory  of  matter,  electric  waves,  physical  optics  and 
physiological  optics;  his  papers  have  appeared  in  the  Optical  Journal,  the 
Keystone  Magazine  of  Optometry,  the  Ophthalmic  Record,  the  Physical  Reciew, 
the  Philosophical  Magazine,  the  Ohio  Journal  of  Science,  the  fi  ellsworth  and  the 
Journal  of  Ophthalmology,  Otology  and  Laryngology.  At  the  present  time  he  is 
the  editor  of  the  newly  founded  Journal  of  Physiological  Optics  published  by 
the  Research  Division  of  the  American  Optical  Company. 

As  a  lecturer  along  optical  lines  he  is  well-known  to  the  readers  of  these 
pages.  He  has  in  every  word  and  act  endeavored  to  promote  the  best  interests 
of  the  practices  of  ocular  refraction. 


Course  No.  14 


Copyright  1920,  by  Department  of  Education, 
American  Optometric  Association 


Optometrical  Courses  of  Study 

arranged  by  The  Department  of  Education 
American  Optometric  Association 

Edited  by  William  S.  Todd, 

Vice  President  of  A.  O.  A.,  and  Chairman  of 

Department  of  Education 

Ocular  Accommodation 

by 
CHARLES  SHEARD,  A.  B.,  A.  M.,  Ph.  D., 

Physiological  Opticist,  The  American  Optical  Company;  for- 
merly Professor  and  Director  of  Applied  Optics,  the  Ohio  State 
University;  Author  of  Physiological  Optics,  Dynamic  Ocular 
Tests,  Dynamic  Skiametry,  and  A.  O.  A.  Course  on  Static  and 
Dynamic  Skiametry,  as  well  as  numerous  researches  and  papers 
dealing  with  visual  optics. 

Other  courses  are  in  preparation  and  will  be   issued   as  soon 
as  possible. 

Write  The  Department  of  Education, 
American  Optometric  Association, 

P.  O.  Box  1042,  Hartford,  Conn., 

for  full  particulars  and  list  of  courses. 

Education  Department 
William  S.  Todd,  Chairman,  Hartford,  Conn. 

Harry  J.  Covelle,  Bangor  Me., 

Ernest  H.  Kiekenapp,  Lake  Benton,  Minn. 

Foreword  by  the  Editor 

This  course  of   Dr.  Sheard's  on    "Ocular   Accommodation" 

is  much  longer  than  was   originally  intended    but  it  was  felt  by 

author  and  editor  that  it  would  be  a  mistake  to  shorten  it.  Students 

who  have  not  procured  Dr.  Sheard's  previous  course  on  "Static 

and  Dynamic  Skiametry,"  issued    by  this  Department,  will  do 

well   to  order   it.     Any   problem    pertaining   to   the    lesson   not 

clear  to  the  student  will    be    answered  if  a  stamped,  addressed 

envelope  accompanies  the  request. 

W.  S.  Todd,  Editor. 


Course  No.  14 
Page  1 


OCULAR  ACCOMMODATION 


Foreword  by  the  Author 

When  we  recall  the  amount  of  attention  which  has  been 
devoted  to  refractive  errors  and  their  correction  it  is  surprising 
that  the  study  of  accommodative  anomalies  has  received  com- 
paratively little  attention  from  students  of  and  practitioners 
upon  the  eye.  Yet  those  who  deal  week  in  and  week  out  with 
the  problems  of  refraction  must  realize  and  appreciate  the  fact 
that  these  anomalies  very  frequently  arise  and  often  occasion 
trouble  and  uncertainties  as  to  the  proper  procedure  to  be 
followed.  Possibly  one  of  the  reasons  why  the  importance  of 
accommodative  anomalies  has  not  been  more  thoroughly  appre- 
ciated lies  in  the  fact  that  there  is  considerable  vagueness  and 
lack  of  clarity  in  our  notions  of  what  is  meant  by  normal  accom- 
modation and  a  lack  of  knowledge  of  the  simple  tests  which 
may  be  easily  and  quickly  made  to  determine  the  amplitude  of 
accommodation.  Probably  nothing  is  as  difficult  in  ocular  work 
as  the  establishment  of  standards,  such  as  those  of  normal  visual 
acuity,  amplitudes  of  accommodation  to  be  normally  (;'.  e. 
on  the  average)  expected  at  various  ages,  normal  duction  powers 
at  distance,  ample  reserve  convergence  at  the  reading  point 
and  so  forth.  Hence,  it  is  in  general  only  possible  to  determine 
when  any  given  accommodative  amptitude  should  be  classed 
as  subnormal  or  supernormal  after  we  have  set  the  limits  of 
normal  accommodative  action. 

And  the  same  remarks  are  as  applicable  to  convergence  as 
to  accommodation.  The  real  significance  of  tonic  muscular 
imbalances,  /'.  e.  the  tests  made  at  twenty  or  more  feet,  duction 
tests  at  distance,  physiologic  exophoria,  accommodative  conver- 
gence and  fusion  convergence,  together  with  a  determination 
ot  the  real  demands  upon  convergence,  the  amount  supplied 
and  the  reserves  at  the  close  working  point  are  unknown  to  many 
practitioners.  Let  it  be  stated  then  in  these  introductory 
remarks  that  the  law  of  supply  and  demand  is  as  applicable 
to  human  eyes  as  to  business.  A  small  drain  is  of  insignificance 
when  the  reserve  is  large,  but  a  normal  demand  may  be  taxing 
if  the  reserves  are  low.  To  illustrate  very  simply,  the  expendi- 
ture of  one  dollar  out  of  ten  leaves  a  good  reserve,  while  the 
spending  of  three  out  of  five  dollars  approximates  the  danger 
line  and  invites  financial  inefficiency.  So  in  accommodation 
or  convergence.  An  accommodative  demand  of  3  diopters  with 
5  diopters  in  reserve  is  readily  met,  whereas  an  accommodative 
demand  of  3  diopters  with  a  reserve  of  2  diopters  otten  entails 
fatigue  and  borders  on  inefrtciencv.     .And  a'j;ain,  a  convergence 


Course  No.  14 
Page  2 

demand  of  loA  with  a  prism  reserve  of  25A  may  signify  a  con- 
dition of  ocular  convergence  which  can  be  comfortably  met, 
whereas  a  demand  of  loA  with  but  6A  of  reserve  doubtless  means 
periods,  either  longer  or  shorter,  of  difficulty  in  securing  the  act 
of  binocular  single  vision. 

Because  of  the  rather  limited  space  at  our  disposal  and  be- 
cause of  the  importance  of  accommodation  in  visual  optics, 
we  shall  confine  our  attention  wholly  to  the  one  topic.  And 
even  then  we  cannot  hope  to  more  than  brush  the  surface.  We 
are  now  laboring  upon  a  rather  exhaustive  treatise  on  Ocular 
Accommodation  and  some  day  hope  to  have  it  finished  and  to 
follow  it  with  a  companion  volume  on  Ocular  Convergence. 

The  writer  recommends  that  the  reader  become  thoroughly 
conversant  with  the  excellent  course  (No.  3  in  the  Optometrical 
Courses  of  Study)  by  Dr.  W.  B.  Needles.  He  will  find  an 
excellent  presentation  of  many  fundamental  facts  upon  the  sub- 
ject of  ocular  muscles  in  general.  The  essay  which  follows  deals 
with  the  function  of  accommodation  only. 


Course   No.  14 
Page  3 

Chapter  I. —  The  Mechanism  of  Accommodation 

We  shall  discuss  in  some  detail  various  phases  and  phe- 
nomena of  accommodation  and  methods  of  testing  the  power 
and  amplitude  of  accommodation  -and  the  significances  of  the 
methods  and  the  findings  in  various  ocular  conditions. 

The  eye  is  the  most  wonderful  of  all  optical  instruments 
in  that  it  possesses  the  inherent  ability,  if  normal,  through  the 
third  nerve  innervation  actuating  the  ciliary  muscles,  to 
change  its  focus  from  infinity  to  its  near  point  in  order  to  throw 
upon  the  retina  a  clear,  sharp  image  of  the  object  viewed.  The 
emmetropic  eye,  fixing  an  object  at  infinity  or,  in  practice,  at 
twenty  feet  (which  involves  an  error  of  about  one-sixth  of  a 
diopter,  which  is  practically  negligible)  is  in  a  static  condition. 
The  word  static  is  to  be  taken  in  its  broadest  sense  since  experi- 
mentation has  shown  fairly  conclusively  that  a  normal  eve 
fixing  a  distant  point  is  in  a  passive  condition  under  the  influence 
of  a  slight  contractility  of  the  ciliary  muscle.  Such  a  statement 
as  this  means,  in  other  words,  that  the  normal  eye,  dissociated 
from  its  mate  and  under  the  guidance  of  the  will,  definitely  re- 
garding an  object  at  twenty  or  more  feet  away,  is  very  slightly 
hyperopic.  This  may  be  due  to  the  fact  that  the  maior  aniount 
ot^  distant  seeing  is  done  within  a  radius  of  thirty  feet  or  less. 
When,  however,  the  refractive  condition  of  the  eve  is  changed 
in  accordance  with  the  distance  at  which  the  object  is  to" be 
viewed  so  as  to  secure  effective  focusing  of  the  image  upon  the 
retina,  accornmodation  is  involved  and  the  ciliary  Ts  in  a  con- 
tractile condition  and  the  crystalline  lens  changes  shape  under 
Its  action.  The  eye  is  then  in  a  dynamic  condition.  Evidentlv 
then  the  static  refraction  of  an  eye'is  that  of  the  whole  eve  when 
accommodation  is  at  rest,  while  the  dynamic  refraction  is  that 
derived  from  accommodation;  hence  the  total  refracting  power 
of  an  eye  is  the  sum  of  the  two. 

It  is  agreed  by  all  that  a  change  from  the  static  to  the 
dynamic  is  accomplished  by  changes  in  curvature  of  the  crys- 
talline lens.  The  classic  experiments  of  Cramer,  Purkinje, 
Helmholtz,  Tscherning,  and  others  have  conclusively  shown 
that  an  alteration  in  curvature,  confined  almost  entirely  to  the 
anterior  surface  of  the  lens,  takes  place  during  accommodation. 
These  and  other  investigators  showed  that  the  catoptric  images 
formed  by  reflection  from  the  surfaces  of  the  crystalline  under- 
went changes  bf)th  as  to  position  and  size  when  accommodation 
was  brought  into  play. 

It  is  presumably  a  correct  statement  of  the  condition  of 
our  knowledge  relative  to  accommodation  when  it  is  asserted 
that  the  scientific  world  is  certain  only  of  the  seat  of  the  accom- 
modative changes  which  are  dynamically  brought  about  through 
the  ciliary  muscle.  Several  theories  have  been  advanced  as 
to  how  these  changes  take  place.     The  two  pre-eminent  theories 


Course   No.  14 
Page  4 

are  those  of  Helmholtz  and  of  Tscherning.  According  to 
Helmholtz,  the  crystalline  lens,  when  in  a  state  of  rest,  is  flat- 
tened to  its  minimum  curvature  by  the  constant  traction  of  the 
ligament.  The  natural  condition  of  the  ligament  is,  then, 
according  to  this  theory,  one  of  tension.  During  accommoda- 
tion, Mueller's  ring  (consisting  of  the  circular  fibres)  and  the 
ciliary  muscle,  which  is  firmly  attached  to  the  sclero-corneal 
border,  contract  and  draw  forward  the  ciliary  processes  as  well 
as  the  periphery  of  the  choroid  with  which  the  suspensory  lig- 
ament is  connected.  The  latter  then  relaxes  its  tension  on  the 
anterior  capsule  and  the  lens,  by  reason  of  its  elasticity,  bulges 
outward  toward  the  cornea  and  so  becomes  more  convex.  The 
theory  ot  Tscherning  is  based  upon  his  experiments  (see  Tschern- 
ing s  Physiologic  Optics)  which  show  that  the  lens  of  the  eye 
during  accommodation  has  a  shape  that  cannot  be  accounted 
for  by  previous  theories.  While  the  central  part  of  the  lens  is 
more  convex,  the  peripheral  part  is  very  much  flattened.  Accom- 
modation is  therefore  eflected  by  a  dynamic  distortion  of  the 
lens,  giving  to  the  anterior  surface  a  curve  approximating  to  a 
hyperboloid  of  revolution.  Tscherning,  therefore,  supposes 
that  the  increase  in  curvature  at  the  central  portion  of  the 
anterior  surtace  of  the  crystalline  lens  and  the  considerable 
flattening  at  the  periphery  are  obtained,  not  by  relaxation,  but 
by  a  direct  traction  of  the  ligament  on  the  periphery  of  the  lens. 
He  supposes  contraction  of  the  ciliary  muscle  on  itself  so  that 
the  posterior  extremity  of  the  ciliary  body  is  advanced  and  the 
anterior  is  receded;  this  contraction  causes  a  pressure  on  the 
vitreous  and  on  the  posterior  surface  of  the  lens  simultaneously 
with  the  tension  exerted  through  the  ligament  on  the  front  sur- 
face of  the  lens.  The  theory  of  Helmholtz  is  at  present  more 
generally  accepted  than  that  of  Tscherning,  but  the  views  of 
this  latter  experimenter  seem  to  account  in  a  more  satisfactory 
manner  for  the  distinct  sense  of  effort  which  results  in  presbyopia, 
accommodation  for  the  near  point  and  sustained  accommoda- 
tion. 

Bowman's  Muscle  and  its  Function  —  Tilting    of    the 
Crystalline  Lens 

A  portion  of  the  ciliary  body  is  composed  of  muscular  fibres 
laid  down  in  flat  bundles  forming  a  sort  of  plexus  and  known 
as  the  ciliary  muscle.  The  fibres  composing  this  muscle  may 
be  classified  as  (i)  meridional,  (2)  radiating  and  (3)  circular. 
This  first  set  of  muscle  fibres,  which  run  parallel  with  the  merid- 
ians of  the  eye,  were  discovered  by  Bowman.  This  muscle  — 
the  so-called  "tensor  of  the  choroid" —  bears  the  name  of  Bow- 
man. The  circular,  sphincter  or  annular  fibres  are  usually 
referred  to  as  the  muscle  of  Mueller;  they  form  a  sphincter 
ring  concentric  with  the  ecjuator  of  the  lens.  The  most  authori- 
tative opinions  upon  the  functions  of  these  two  muscles  indicate 
that  the  Bowman's  muscle  is  the  active  agency  in  keeping  the 


Course  No.  14 
Page  5 

crystalline  lens  in  its  correct  position  in  its  bed  in  the  anterior 
part  of  the  vitreous,  while,  on  the  other  hand,  the  Mueller 
muscle,  by  its  contraction,  is  the  active  agent  in  effecting  a  change 
in  the  refractive  power  of  the  lens  equally  in  all  meridians,  the 
elasticity  of  the  lens  being  the  passive  agent. 

In  the  progress  of  the  development  of  the  eye,  the  passive 
position  assumed  by  the  lens  in  its  development  may  not  be 
correct,  hence  the  need  for  some  active  or  readjusting  agent. 
This  function  is  doubtless  fulfilled  by  the  muscle  of  Bowman, 
which,  under  the  guidance  of  retinal  sensations  (since  the  center 
of  the  macula  is  the  center  of  fixation),  comes  to  the  aid  of  this 
readjustment.  It  may  also  happen  that  a  corneal  astigmatism 
may  be,  in  part  or  in  whole,  offset  by  a  lenticular  condition  or 
tilting  of  the  lens  brought  about  by  this  muscle  acting  as  the 
active  agent  in  producing  a  lenticular  astigmatism  at  right  angles 
to  the  corneal  astigmatism  for  the  purpose  of  neutralizing  it. 
It  can  be  mathematically  shown  that  when  a  spherical  lens  is 
rotated  about  any  diameter  there  will  be  produced  by  this 
obliquity  of  the  spherical  lens  a  slightly  stronger  sphere  com- 
bined with  a  cylinder  whose  axis  corresponds  to  the  axis  of 
rotation.  The  formulae  for  the  cylindrical  effects  of  oblique 
sphericals  as  usually  given  are  of  a  complex  form,  (see  for  instance 
their  development  in  A.  S.  Percival's  Optics)  but  the  simple 
relations  which  follow  in  the  succeeding  sentence  may  be  found 
in  Laurance's  General  and  Practical  Optics.  If  F  represents 
the  focal  length  of  the  lens  and  Fi  and  Fi  indicate  the  effective 
focal  lengths  of  the  meridians  of  greatest  and  least  power, 
while  "tf"  represents  the  angle  of  tilt  ot  the  lens,  then  it  can  be 
shown  that 

(i)     Fi  =  F3  cos-  a 

(,)     p^^F(3-sin^i) 

Thus,  for  example,  if  the  crystalline  lens  has  a  power  of  16.66 
diopters  in  situ.,  and  it  should  be  tilted  about  an  axis,  horizontal 
and  at  right  angles  to  the  antero-posterior  axis  of  the  ocular 
system,  by  an  angular  amount  of  10  degrees,  calculations  show 
that  F  equals  6  cm.,  Fi  equals  5-9j8  cm.  and  Fj  equals  5.758  cm. 
Approximately  then,  Di  (the  dioptric  value  of  F,)  equals  17.36 
diopters  and  Dj  equals  16.82  diopters,  which  are  equivalent  as 
a  sphero-cylinder  to  +16.82  D.  S.C+-5  cyl.  axis  180  (prac- 
tically). We  have,  then,  by  this  tilting  of  the  crystalline  lens 
by  an  angular  amount  of  10  degrees  an  increased  spherical 
power  of  about  0.16  (one-sixth)  diopter  coupled  with  a  half 
diopter  cylinder  axis  horizontal.  And  again,  if  this  same 
crystalline  of  16.66  D  is  tilted  or  rotated  20  degrees  about  a 
horizontal  axis  there  will  result  the  following  approximately 
accurate  sphero-cylindrical  combination,  to  wit:  +17.33  D.  S. 
C  +  2.65   cyl.   ax.    180,   thus    showing    an   increase   of   spherical 


Course  No.  14 
Page  6 

power  of  practically  +0.6  D   coupled  with   a   cylindrical   effect 
of  about  +2.75  D, 

The    Function  of  Mueller's  Muscle  and  of  the  Iris 

The  contraction  ot  Mueller's  muscle  is  for  the  purpose  of 
increasing  the  refractive  power  of  the  crystalline  lens  equally  in 
all  its  meridians  in  the  interests  ol  improvement  of  vision.  If 
the  eye  is  ametrcpic  this  muscle  will  respond  under  the  subject's 
desire  for  sharper  vision  it  such  action  will  improve  matters. 
The  hyperope,  looking  at  infinity,  will  accommodate  in  the 
interests  ot  bringing  the  images  in  focus  upon  the  retina  where 
possible.  This  means  a  reduction  in  the  size  of  the  diffusion 
circles  with  consequent  improvement  in  sharpness  of  images 
and  is  accomplished,  without  doubt,  by  two  factors,  the  first 
of  which  is  the  chief  one,  namely:  (a)  change  of  lens  shape 
under  ciliary  action  and  (b)  reduction  in  pupillary  area,  since 
the  act  of  accommodation  is  always  normally  accompanied  by 
convergence  (which  may,  however,  be  suppressed  or  made 
non-effective  by  fusion  divergence)  and  pupillary  contraction. 
It  seems  likely,  therefore,  that  a  hyperope  of  1  D,  for  example, 
does  not  necessarily  constantly  use  2  D  of  ciliary  innervation  to 
cause  2  D  of  lens  change  in  order  to  correct  his  ametropia  at 
distance,  since  he  is  aided  in  his  fundamental  desire  for  sharpness 
and  clearness  of  vision  by  the  normally  accompanying  contrac- 
tion of  the  pupil.  This  assistance  furnished  by  the  contracted 
pupil  may  permit  the  hyperope  to  see  clearly  by  means  of  an 
accommodative  effort  of  slightly  lesser  amount  than  his  error. 

The  writer  has  made  observations  upon  a  considerable 
number  of  cases  of  hyperopia  of  from  i  D.  to  3  D.  error  as  to 
the  size  of  the  pupils  before  wearing  corrections  and  some  weeks 
thereafter,  the  examinations  being  made  under  as  nearly  identical 
conditions  as  possible,  and  has  come  to  the  conclusion  that  a 
relief  of  the  ciliary  from  overtaxation  is  accompanied  by  a  small 
but  perceptible  increase  in  the  size  of  the  pupil.  Such  an  in- 
crease in  the  size  of  the  pupil,  even  though  it  may  be  small, 
produces  a  corresponding  increase  in  the  size  of  the  diffusion 
circles,  and  since  the  visual  acuity  decreases  with  increase  in 
the  size  of  pupillary  area  we  have  another  factor  other  than  the 
relaxation  of  excessive  ciliary  action  to  consider  in  the  pre- 
scribing of  convex  lenses  in  hyperopia. 

A  lens  correction  which  may  slightly  blur  distant  vision 
may  in  a  little  time  prove  satisfactory  because  of  ciliary  relief 
and  because  of  reduced  visual  acuity  on  account  of  pupillary 
change.  The  converse  of  this  proposition  seems  to  be  equally 
true,  for  myopes  cannot  accommodate  beyond  their  far-points, 
for  a  use  of  their  accommodation  would  only  render  them  more 
myopic.  Myopes,  as  a  general  rule,  have  rather  large  pupils. 
When  properly  corrected,  such  persons  do  not  accommodate 
at  infinitv,  but  see  at  distance  normallv  and  do  accommodate 


Course   No.  14 
Page  7 

between  the  far  and  near  points.  Under,  therefore,  the  produc- 
tion of  normal  accommodative  action  the  pupils  will  be  slightly- 
constricted,  in  general,  in  distance  seeing  as  compared  with  their 
initial  conditions  without  correcting  lenses;  this  condition  of 
affairs  will  cause  a  slight  decrease  in  the  sizes  of  the  diffusion 
circles  and  hence  add  to  the  clarity  of  vision.  Is  it  not  then  pos- 
sible that  this  is  an  important  factor  in  the  determination  of 
the  proper  myopic  correction  and  that  it  gives  us  an  added  reason 
for  the  under-correction  of  myopia  in  generaP 

The  writer  takes  occasion  to  quote  the  following  from  an 
article  by  C.  F.  Prentice  on  "  The  Iris,  as  Diaphragm  and  Photo- 
stat: —  "The  aperture  ot  the  diaphragm  must,  therefore,  have 
a  definite  and  specific  diameter  for  every  optical  instrument 
if  we  are  to  secure  maximum  definition  and  illumination  without 
aberration.  The  proper  diaphragm  is,  therefore,  one  of  the 
most  important  and  indispensable  parts  of  every  compound 
dioptric  system.  The  human  eye  is  such  a  system  and  is  pro- 
vided with  its  diaphragm  —  the  iris.  In  the  eye,  which  is  a 
dynamic  apparatus  given  to  variations  of  power,  a  fixed  diameter 
of  pupil  would  fail  to  theoretically  fulfill  the  requirements. 
When  the  eye  is  in  a  state  of  accommodation,  it  becomes  a 
stronger  refracting  system  and  therefore  needs  a  smaller  aperture 
of  diaphragm,  hence  the  pupil  contracts."  Yet  Helmholtz 
says:  "Von  Graefe  observed  in  an  eye  from  which  he  had  re- 
moved the  iris  by  operation  that  the  normal  range  of  accommo- 
dation was  still  present."  He  concludes:  "The  iris,  therefore, 
does  not  play  an  important  role  in  accommodation."  So  far 
as  the  above  noted  measurements  are  concerned,  such  a  con- 
clusion may  be  quite  correct,  yet  if  construed  in  its  broadest 
sense  it  discountenances  the  value  of  the  iris  as  a  diaphragm 
entirely." 

It  is  nevertheless  universally  admitted  that  the  iris  does 
act  independently  of  and  simultaneously  with  accommodation. 
Bonders,  in  his  well  known  treatise  on  refraction,  says:  "Move- 
ments of  the  iris  are  nevertheless  associated  with  accommo- 
dation; they  are  governed  by  the  same  nerves  as  the  latter,  so 
that,  until  the  mechanism  of  accommodation  is  better  under- 
stood, a  direct  relation  between  them  may  not  be  looked  upon  as 
improbable."  When  the  iris  acts  independently  of  the  accommo- 
dation it  acts  as  a  photostat,  regulating  the  volume  ot  light 
incident  upon  the  retina.  There  must  exist,  as  Prentice  points 
out,  a  subtle  and  synchronous  balance  between  retinal  perception, 
uveal  stimulus  and  iritic  response. 

A  simple  experiment  will  illustrate  in  part  the  main  ideas 
involved  in  these  remarks:  If  an  emmetrope  places  a  i  D 
convex  lens  before  his  eye,  the  normal  20-foot  line  becomes 
indistinct  with  an  approximate  reduction  in  acuity  to  6 '9.  If 
the  lens  is  now  covered  with  a  fine  pin-hole  disk,  normal  acute- 
ness  of  vision  will  be  re-established.     If  the  actual  myopic  eye 


Course   No.  14 
Page  8 

does,  under  proper  correction  of  its  refractive  error,  have  thereby 
re-established  proper  pupillary  size  and  sphincter  action  in 
accompaniment  with  accommodation  and  it  we  can  apply  by 
analogy  the  reasoning  from  the  above  optical  experiment  with 
artificial  myopia  and  reduced  artificial  pupil,  we  can  appreciate 
the  influence  which  the  size  of  the  pupil  may  have  in  subjective 
findings.  This  is  likewise  probably  one  of  the  reasons  why  the 
retinoscopic  findings  representing,  if  properly  made  along  the 
visual  axial  line,  the  actual  refractive  error  may  not  agree  ;';/ 
toto  with  the  subjective  findings  made  when  the  eye  views  an 
illuminated  chart  at  distance  and  its  pupil  has  its  effect  upon  the 
visual  acuity  findings.  This  subject,  the  writer  believes,  is 
worthy  of  a  series  of  careful  investigations. 

The   active   agent   in   producing   changes   in    the  refractive 
power  of  the   crystalline   lens  is    the    Mueller   muscle   and    the 
passive  agent  is  the  condition  or  elasticity  of  the  lens.     In  the 
condition   of  emmetropia,   therefore,    no    accommodative    action 
is  demanded  at  infinity  and  images  of  distant  objects  are  definitely 
focused   upon    the   retina.     An    object    viewed   monocularly    at 
thirteen  inches  demands  normally  3  D.  of  innervation  and  3  D. 
of  resultant  lenticular  change.     Binocularly,  no  accommodation 
and  no  convergence  are  normally  demanded  at  infinity  (twenty 
feet);     at   thirteen   inches  3    D.   of  resultant   lenticular   change 
in  refractivity  in  each  eye  are  demanded  together  with  an  amount 
of  convergence  partially  and,  in  fact,  largely  furnished  through 
the  association  between  the  brain  centers  controlling  the  ciliary 
muscle  and  convergence,  together  with  the  assistance  afforded 
by  fusional  convergence,  such  that  the  fixation  and  accommo- 
dative points  are  one  and  the  same  and  harmony  exists  between 
these   correlated   functions.     In   hyperopia  or   hyperopic   astig- 
matism  there  is  a  call  for  activity  on   the  part  of  the  ciliary 
muscle    for    both    near   and   distant   seeing.     In    hyperopia    the 
accommodation,    unassociated    with    convergence,    must    effect 
an  increase  of  the  refractive  power  of  the  lens  such  as  will  render 
the  image  of  the  object  of  fixation  sharp  and  clear.     But  the 
necessity  for  the  exercise  of  accommodation   tor  distant  vision 
is  commonly  said  to  disturb  the  relations  between  accommodation 
and  convergence    with  the  usual    exhibition,  upon  test,   of  eso- 
phoria.     In    hyperopic    astigmatism    it   is    the    function    ot    the 
Mueller  muscle  to  put  the  circle  of  least  confusion  in  the  focal 
interval    on    the    macula.     In    myopia   or    myopic    astigmatism 
there  is  no  demand  upon  the  ciliary  muscle  to  do  the  work  when 
the  object  of  fixation  is  in  the  distance.     In  simple  myopia,  no 
accommodation  is  demanded  until  the  object  is  brought  inside 
of  the  patient's  far-point.      In  myopic  astigmatism  the  accom- 
modative  muscles   will    be    brought   into   play   only    when    the 
eyes  are  used  in  near  vision  and  for  the  purpose  ot  placing  the 
focal  interval  on  the  macula.     This  work  of  the  ciliary  muscle 
in  improving  vision  in  the  near  when  there  is  a  low  degree  of 
myopia  is  abnormal  work,  however,  even    though  it  is  a  lesser 


Course   No.  14 
Page  9 

amount  than  is  demanded  in  emmetropia.     There  is,  therefore, 
normally  associated  in  such  myopic  cases  a  condition  of  exophoria. 

Origin  of  Anomalies  of  Accommodation 

Accommodation  is  a  function  ot  the  ciliary  muscle  and  of 
the  crystalline.  The  anomalies  of  accommodation  must,  there- 
fore, find  their  origin  in  changes  and  alterations  of  one  or  the 
other  of  these  two  factors  or  of  both  of  them.  The  diminution 
of  elasticity,  to  which  the  crystalline  is  subject  from  early 
childhood  on,  is  the  cause  of  the  gradual  decrease  of  the  ampli- 
tude of  accommodation  and  of  its  total  annihilation  toward  the 
age  of  seventy-fiv'e  years.  If  the  crystalline  becomes  rigid 
from  any  other  cause  than  senility  the  effect  upon  the  accommo- 
dation will  be  the  same.  It  appears,  however,  from  ophthalmic 
literature  that  cases  of  this  kind  are  rare.  Probably  in  all 
cases  the  lens  becomes  inelastic  when  it  becomes  opaque  but 
the  changes  in  structure  which  produce  cataract  are  accompanied 
by  visual  disturbances  of  such  a  pronounced  character  as  to 
cause  the  diminution  in  the  amplitude  of  accommodation  to 
vanish  into  the  background  as  of  secondary  importance._  It 
may  occasionally  happen  that  the  crystalline  is  separated  from 
its  attachment  with  the  suspensory  ligament,  the  zone  of  Zinn 
being  ruptured  in  part,  producing  a  subluxation  but  still  per- 
mitting the  lens  to  occupy  the  pupillary  space.  Such  a  rupture 
would  cause  the  lens  to  assume  its  most  convex  form  and  bring 
the  refraction  of  the  eye  to  a  maximum  and  hence  abolish  accom- 
modation. 

Changes  in  the  dynamic  refraction  of  the  eye  due  to  crystal- 
line changes  are  less  frequent  than  those  resulting  from  irregu- 
larities in  the  operation  of  the  ciliary  muscle.  We  have,  there- 
fore, to  differentiate  between  and  to  consider  spasm,  weakening, 
paresis  and  paralysis  of  the  ciliary  muscle. 

Some    Anatomical    and    Physiological    Facts    Relative     to 
the  Accommodative  Apparatus  of  the  Eye 

In  entering  into  the  presentation  of  what  we  have  to  say 
upon  the  topic  of  the  anomalies  of  accommodation  we  beg  the 
reader's  indulgence  while  we  quote  the  foUovying  paragraphs 
recalling  a  few  anatomical  and  physiological  facts  relative  to 
the  accommodative  mechanism  of  the  eye.  These  paragraphs 
are  taken  from  Landolt's  "  The  Refraction  a7jd  Accommodation 
oj  the  Eyey 

"The  innervation  of  Brueck's,  or  of  the  ciliary,  muscle  is 
furnished,  as  Henson  and  Voelkers  have  demonstrated,  by  the 
branches  of  the  ciliary  ganglion.  As  they  also  innervate  the 
iris,  and  since  the  movements  of  this  diaphragm  are  intimately 
associated  with  those  of  accommodation,  and  since,  moreover, 
the  physiology  of  the  ciliary  ganglion  has  scarcely  been  studied 
except  With  reference  to  the  pupillary  movements,  we  will  re- 


Course  No.  14 
Page  10 

capitulate,  in  a  few  words,  the  action  of  this  ganglion  upon  the 
iris.  The  ciliary  ganglion  sends  to  the  muscle  of  accommodation 
and  to  the  iridian  diaphragm  some  fifteen  nerve  branches,  the 
short  ciliary  nerves.  They  perforate  the  sclerotic  in  the  vicinity 
of  the  optic  nerve.  .  .  .  The  afferent  branches  of  the 
ciliary  ganglion  arise  from  three  sources:  (i)  From  the  common 
motor  oculi  (motor  root);  (2)  from  the  trigeminus,  through  the 
intermediation  of  the  naso-cilaris  (sensory  root);  (3)  from  the 
great  sympathetic  (vegetative  root).  The  first  of  these  roots 
appears  to  hold  under  its  sole  dependence  the  working  of  the 
accommodative  muscle  (Trautvetter)  and  of  the  sphincter  of 
the  iris.     H.   Mayo's  experiments  have      .      .  indubitably 

proved  that  the  irritation  of  this  nerve  produces  a  contraction 
of  the  pupil.  Pathology  demonstrates,  too,  that  paralysis  of 
accommodation,  as  well  as  the  mydriasis  which  often  accompanies 
it,  is  due  to  lesions  of  the  third  pair  or  of  the  motor  root  which 
it  gives  to  the  ciliary  ganglion.  The  vegetative  root,  emanating 
from  the  great  intercranial  sympathetic,  controls  the  dilator 
of  the  pupillary  orifice  (Petit,  Budge,  and  Waller).  It  was 
long  ago  established  that  the  experimental  or  pathological 
irritation  of  the  great  sympathetic,  in  the  neck,  provokes  mydria- 
sis, and  that  the  section  or  paralysis  of  the  same  nerve  entails 
the  preponderance  of  the  pupillary  sphincter.  As  to  the  root 
furnished  by  the  trigeminus  it  very  probably  contains  only 
sensory  fibres. 

"The  contraction  of  the  ciliary  muscle  and  that  of  the 
sphincter  of  the  pupil  are  almost  always  simultaneously  exerted, 
while  relaxation  of  the  accommodation  is  usually  accompanied 
by  dilation  of  the  pupil.  These  two  acts  are  not,  however, 
indissolubly  associated  with  each  other.  We  have  only  to 
recall  the  fact  that  the  pupil  contracts  and  dilates  under  the 
influence  of  variations  in  illumination,  without  the  accommoda- 
tion undergoing  any  change.  The  reflex  movement  ot  the  iris 
remains  intact,  not  only  when  the  accommodation  is  abolished 
entirely  by  the  rigidity  of  the  crystalline,  but  also  in  many  cases 
of  paralysis  of  the  ciliary  muscle.  Inversely,  immobility  of 
the  pupil,  under  the  influence  of  light  as  well  as  under  that 
of  accommodation,  has  been  observed  when  the  ciliary  muscle 
worked  normally. 

"Changes  in  the  accommodation  are,  therefore,  generally, 
though  not  always,  accompanied  by  modifications  in  the  diameter 
and  mobility  of  the  pupil.  Spasm  of  accommodation  coincides 
with  myosis  and  paralysis  with  mydriasis.  In  these  two  condi- 
tions the  pupil  presents  a  diminution  of  contractility  or  even 
complete  immobility  under  the  accommodative  impulsion. 
Nevertheless,  the  iris  reacts,  in  a  certain  degree,  to  variations 
of  illumination  unless  there  be  complete  paralysis  ot  the  ciliary 
fibres  of  the  third  pair.  In  ataxia,  the  contrary  is  observable. 
The  pupils,  contracted  under  the  influence  of  the  preponderant 
tonicity  of  the  sphincter,  which  is  no  longer  compensated  by  the 


Course   No.  14 
Page  11 

action  of  the  dilator  fibres,  cease  to  respond  to  luminous  excita- 
tion but  still  contract  under  the  influence  of  accommodation. 

"The  capital  symptom  of  an  anomaly  of  accommodation 
is  the  change  in  position  of  the  punctum  proximum  or  of  the 
punctum  remotum,  as  well  as  the  visual  disturbances  resulting 
from  it. 

"Non-artificial  spasm  of  accommodation,  /'.  e .^  that  which  is 
not  provoked  by  myoptics,  brings  the  punctum  remotum  nearer, 
without  altering  the  position  of  the  punctum  proximum.  Paresis 
of  the  accommodation  causes  recession  of  the  punctum  proxi- 
mum, without  influencing  the  punctum  remotum.  Hence  both 
affections  reduce  the  amplitude  of  accommodation,  the  spasm 
at  its  farther  extremity  and  paresis  at  its  nearer. 

"Now  accommodation  is  in  inverse  ratio  to  age  and,  although 
this  relation  is  not  absolute  and  mathematical,  it  nevertheless 
admits  of  less  latitude  than  most  physiological  laws.  Bonders' 
table  corresponds,  with  almost  surprising  accuracy,  to  reality; 
so  that,  whenever  the  amplitude  of  accommodaton  is  less  than 
that  required  by  Bonders'  law,  there  is  reason  to  seek  some 
pathological  cause  of  its  restriction." 

The   Theory   Underlying   the  Determination    of   the 
Amplitude  of  Accommodation 

The  amplitude  of  accomniodation  is,  as  we  have  seen,  the 
increase  in  the  refractive  power  that  the  eye  can  assume  by 
means  of  the  contraction  of  its  ciliary  muscle.  The  theory  of 
the  determination  of  the  amplitude  of  accommodation  as  laid 
down  by  Bonders  and  Landolt  in  the  early  days  of  ophthal- 
mological  and  optometric  development  demands  that  the  re- 
fraction, /),  of  the  eye  which  it  attains  under  the  maximum 
curvature  of  the  crystalline  lens  be  known  in  addition  to  the 
refraction,  r,  of  the  eye  when  at  rest.  The  difl^erence  between 
the  two  is  the  amplitude  of  accommodation,  a.  This  is  mathe- 
matically expressed  as 

a  =  p  — r 

The  static  refraction,  7%  i.  e.^  its  minimum  refraction,  is  corre- 
lated with  the  punctum  remotum  R  by  the  equation 


R 

So,  in  turn,  the  maximum  refraction  of  the  eye,  or  that  which  it 
possesses  when  atlapted  to  the  nearest  point  or  punctum  prox- 
imum P,  is  the  inverse  of  this  distance  P,  or 

I 

P  =  — 


Course   No.  14 
Page  12 

Acccirding  to  our  classic  methods,  therefore,  the  amplitude  of 
accommodation  depends  for  its  value  upon  the  accurate  deter- 
mination of  (i)  the  static  condition  of  the  eye  and  (2)  its  near 
point.  We  shall,  a  little  later,  point  out  some  factors  which 
limit  our  accuracy  in  the  determinations  of  either  of  these 
quantities.  This  is,  then,  the  classic  method  of  theoretically 
and  practically  determining  the  amplitude  of  accommodation. 
A  knowledge  of  the  patient's  static  refraction  and  of  his  near 
point  has  been  generally  accepted  as  giving  a  satisfactory 
determination  of  the  patient's  total  and  available  accommoda- 
tion. We  shall  point  out  in  some  ot  the  succeeding  paragraphs 
that  the  finding  of  the  near  point  by  any  of  the  methods  com- 
monly in  vogue  may  lead  to  very  faulty  conclusions  as  to  the 
total  available  accommodation  when  the  patient  is  engaged 
in  near  work  at  the  usual  reading  and  working  distance.  The 
question  of  the  ability  of  the  ciliary  muscle  and  the  crystalline 
lens  to  function  normally  in  all  cases  is  not  settled  by  a  deter- 
mination of  the  near  point  either  monocularly  or  binocularly. 

Assuming  tor  the  present  that  the  far  and  near-points  can 
be  accurately  located  by  some  method  and  that  these  deter- 
minations give  what  the  classical  theory  and  method  say  they  do, 
we  know  that  when  the  eye  is  totally  relaxed  it  is  in  a  condition 
of  static  or  minimum  refraction  and  is  adjusted  for  its  far-point 
and  that  when  it  is  in  its  maximum  dynamic  condition  it  is 
adjusted  for  its  near-point.  If  the  far-point,  R,  is  100  cm.  and 
the  near-point,  P,  is  10  cm.,  then  R  — P  =  90  cms.;  this  is  also 
the  range  of  accommodation.  The  amplitude  (from  the  equa- 
tion a  =  p  — r)  would  be  practically  loD  — iD  =  9D.  Theoreti- 
cally, however,  this  is  not  accurate  if  the  near  point  is  deter- 
mined by  means  of  lenses  inserted  at  the  usual  distance  from  the 
eye;  nor  again,  does  the  lens,  equivalent  dioptrically  to  100  cms. 
focus,  contribute  exactly  i  D.  ot  lenticular  power  it  placed  other 
than  in  contact  with  the  eye.  This  is  an  impossibility.  To 
illustrate:  if  the  distance  of  the  punctum  remotum  from  the 
myopic  eye  is  125  mms.,  then  the  correcting  lens  placed  15 
millimeters  in  front  of  the  cornea  will  need  to  have  a  tocal 
length  of  125  —  15=110  mms.,  which  corresponds  to  9  D.  Hence 
a  concave  9  D.  lens  corrects  a  myopia  of  8  D.  The  same  reason- 
ing holds  in  hyperopia;  for  if  the  punctum  remotum  should  be 
determined  as  lying  1 1 1  mms.  behind  the  refracting  plane  of 
the  eye  there  is  a  hyperopia  of  9  D.  If  the  correcting  lens  is 
placed  15  mms.  before  the  eye,  such  a  correcting  lens  must 
have  a  focal  length  of  Iii-fi5  =  i2;  mms.  focal  length  or  a 
refractive  power  of  8  D.  If  then  the  near-point  of  an  emme- 
tropic eye  is  at  10  cms.,  this  is  dioptrically  equivalent  to  to  D. 
and  we  can  say  that  the  dynamic  refraction  of  the  eye  must  have 
developed  10  D.  of  lenticular  change.  If,  however,  we  should 
represent  the  accommodative  power  in  terms  of  the  equivalent 
amount  of  concave  lens  which  it  can  overcome,  these  lenses 
being  situated,  for  example,  at  15  mms.  from  the  cornea,  it  is 
apparent   in    this   case    that    the   amplitude   of  accommodation 


Course   No.  14 
Page  13 

1000 

would  be  expressed  as =  8.8    D.    practically.     This    ex- 

100+15 

plains  in  part  why  various  tests  for  determining  amplitudes  of 
accommodation  by  near-point  and  concave  lens  methods  vary 
and  why  the  concave  lens  methods  always  indicate  lesser  values. 

When  a  hyperope  or  myope  is  corrected  for  distance  we 
generally  say  that  there  is  need  of  3  D.  of  accommodation  when 
reading  at  2>2  cms.  Theoretical  calculations  (similar  to  those 
given  in  Laurance,  Visual  Optics,  pages  274-275)  show  that  a 
hyperope  ot  5  D.,  wearing  his  distance  correction,  must  accommo- 
date about  3.38  p.  when  reading  at  13  inches,  while  a  myope 
of  5  D.,  corrected  tor  distance,  need  use  only  2.38  D.  of  accommo- 
dation. If  such  is  the  case  and  we  test  for  the  amplitude  of 
accommodation  by  any  near-point  or  concave  lens  method, 
it  is  apparent  that  the  patient  under  test,  wearing  distance 
corrections  and  therefore  supposedly  rendered  artificially  emme- 
tropic, would  show  different  near  points  or  overcome  different 
amounts  of  concave  lens  power  although  each  might  inherently 
possess  the  same  amplitude  of  accommodation,  barring,  of 
course,  such  factors  as  age  and  so  forth.  Such  results  as  these 
indicate,  as  the  above  calculations  show,  that  cases  of  hyperopia 
need  stronger  lenses  for  near  work,  and  cases  of  myopia  tull 
distance  corrections.  The  writer  does  not  find  in  any  literature 
known  to  him  any  researches  in  which  the  amplitudes  of  accom- 
modation for  hyperopes  and  myopes  of  fairly  high  and  equal 
amounts,  with  ages  and  other  ocular  conditions  on  a  par,  are 
recorded.  All  results  for  a  common  age  period  are  usually 
averaged.  This  is  a  problem  worthy  of  investigation  because 
of  its  bearing  upon  the  strengths  of  the  lenses  to  be  prescribed. 
If  the  hyperope,  when  statically  corrected,  must  needs  develop 
something  approximating  10  per  cent,  more  accommodation 
at  23  cms.  than  is  ordinarily  assumed  to  be  demanded  and  if 
the  myope,  when  statically  corrected,  need  develop  about  the 
same  percentage  less,  these  conditions  would  have  an  important 
bearing  on  a  good  many  phases  of  ocular  refraction.  It  would, 
tor  example,  give  a  rational  explanation  for  the  frequent  abnormal 
esophoric  condition  at  near  points  as  compared  with  infinity 
tests  in  hyperopes  and  the  exophoria  ordinarily  associated  with 
myopia.  The  small  number  of  cases  in  my  possession,  in  which 
the  refractive  error  is  fairly  high  and  not  complicated  with 
any  appreciable  astigmia  and  in  which  all  the  necessary  data  are 
available,  indicates  that  the  myopes  show,  on  an  average,  some- 
thing approximating  15  per  cent,  greater  amplitude  of  accom- 
modation. It  is  not  common  to  find  hyperopes  of  twenty  years 
of  age,  tor  example,  showing  in  excess  of  '^.'^  to  9  D.  amplitude 
when  using  concave  lenses  with  No.  2  Jaeger  type  (V' =  .62  D.) 
at  the  thirteen  inch  reading  point  as  the  basis  of  the  test;  but 
myopes  of  about  the  same  age  quite  commonly  show  10  and 
frequently  1 1  D.  under  the  same  method  of  testing. 


Course  No.  14 
Page  14 

Chapter  II. — The  Determination  of  the  Far-Point 

The  Far-point  and  the  Influence  of  Various  Factors  Upon 
Its  Determination  by  Subjective  Methods  ^^^ 

Theoretically  the  far-point  is  easily  determined  through 
a  determination  of  the  distance  correction  for  the  ametropia 
present.  Such  a  statement  of  necessity  raises  the  question 
as  to  the  accuracy  of  the  various  methods  of  static  retraction. 
The  static  methods  are  of  two  general  classes:  (a)  subjective 
and  (b)  objective.  The  subjective  tests  must  of  necessity  be 
based  extensively  upon  visual  acuity  tests,  while  the  objective 
methods  are  largely,  if  not  entirely  at  the  present  time,  those 
peculiar  to  retinoscopy. 

Subjectively,  then,  the  situation  of  the  punctum  rernotum 
is  determined  by  means  of  the  distinctness  of  the  retinal  image. 
The  astronomical  researches  of  Hooke  and  the  physiological 
investigations  of  Helmholtz,  Snellen  and  Javal  have  given  us 
normal  visual  acuity  standard  letters  which  are  arranged  so  as 
to  be  seen  under  an  angle  of  5  minutes,  while  the  lines  which  form 
the  letters  and  most  of  the  intervals  which  separate  them  are 
seen  under  an  angle  of  i  minute.  It  is  well  known,  however, 
that  some  of  the  letters  are  more  easily  read  than  others  on 
the  same  line;  hence  an  operator  is  safe  only  in  saying  that  a 
patient's  visual  acuity  is  "such  and  such  an  amount  according 
to  his  chart."  In  order  to  remedy  this  defect  and  introduce 
an  international  standard  the  split  ring  of  Landolt  has  been 
proposed,  and  in  many  respects  this  seems  more  desirable  than 
our  older  Snellen  letters. 

A  method  for  the  expression  of  the  degrees  of  acuteness  of 
vision  which  can  be  used  in  all  languages  and  which  aims  to 
give  an  official  international  standard  of  acuity  was  adopted 
by  the  International  Ophthalmological  Congress  of  1909.  The 
test-type  thus  officially  adopted  is  the  invention  of  E.  Landolt 
and  is  known  as  the  broken  ring  test.  The  following  are  the  six 
general  principles  laid  down  by  the  Congress  of  1909  relative 
to  the  essential  features  underlying  the  expression  of  the  visual 
acuity:  (i)  The  test  is  based  upon  the  "minimum  separabile" 
or  the  capacity  to  perceive  an  interruption;  (2)  the  test  is  to  be 
made  by  means  of  a  black  ring  on  a  white  ground,  the  ring  to 
be  broken  at  one  place  for  a  space  equal  to  the  width  ot  the 
limb  of  the  ring,  which  is,  in  turn,  one-fifth  of  its  diameter; 
(3)  the  visual  acuteness  is  to  be  expressed  in  relation  to  the 
smallest  angle  under  which  this  can  be  deciphered;  that  is, 
to  the  maximum  distance  at  which  this  can  be  done;  (4)  the 
visual  angle  of  one  minute  is  the  standard  of  comparison;  (5) 
the  mode  of  expression  is  to  be  either  in  decimals  or  as  a  fraction 
(V  =  d/D)and  (6)  the  eye  is  to  be  tested  only  at  a  distance  from 
the  test-object.      Edward  Jackson   {Ophtha'hnic  Record,  March, 


Course  No.  14 
Page  15 

1916)  in  an  article  on  "Cards  for  Sight  Testing  in  Schools," 
points  out  some  of  the  features  of  superiority  of  the  international 
test  of  visual  acuity.  He  mentions:  (i)  It  is  a  fixed  or  con- 
stant standard.  This  is  impossible  with  test  letters.  (2)  It 
is  unlearnable.  With  the  broken  ring  it  is  only  needful  to  con- 
ceal the  card  and  turn  it  and  a  new  test  is  obtained.  (3)  The 
test  is  more  exact  and  easier  to  understand  because  it  is  made 
at  a  variable  distance.  In  the  ordinary  Snellen  letter  plan 
there  is  no  provision  for  intermediate  grades,  between,  say, 
20/20  and  20/30.  But  with  the  test  card  of  broken  rings  of 
a  single  size  the  acuteness  of  vision  is  ascertained  by  noting 
the  distance  at  which  they  can  be  seen  and  this  distance  can  be 
noted  to  any  fraction  of  a  meter  or  foot  that  seems  desirable. 
(4)  The  apparatus  required  for  the  test  is  much  simpler,  less 
expensive  and  more  convenient  to  handle  than  the  cards  of 
test  letters. 

In  general,  these  same  points  of  advantage  are  applicable 
to  office  practice  as  well  as  to  sight  testing  in  schools.  The 
question  of  the  adoption  of  a  standard  test  on  the  part  of  all 
practicing  retractionists  is  a  vital  one  and  is  worthy  of  considera- 
tion by  readers  of  these  paragraphs.  Many  believe  that  the 
charts  of  test  letters  in  common  use  in  consulting  room  prac- 
tice are  admirably  adapted  to  the  subjective  determination  of 
errors  of  refraction  but  that,  as  a  test  for  visual  acuity,  they 
give  the  poorest  and  most  inexact  standard. 

The  Far-point  and  the  Influence  of  Various  Factors  Upon 
Its  Determination  by  Objective  Methods 

The  skiascopic  and  ophthalmometric  findings  constitute 
the  results  by  objective  methods  which  are  of  value  in  refractive 
work.  The  ophthalmoscope  as  a  refractive  instrument  has 
long  since  been  superseded  by  other  objective  devices:  the 
ophthalmometric  findings  and  their  diagnostic  value  have  been 
discussed  elsewhere  by  Ryer.  In  the  writer's  opinion  it  is  best 
to  make  an  ophthalmoscopic  examination  as  one  of  the  first 
steps  in  all  ocular  investigations,  chiefly  for  the  purpose  of 
determining  upon  the  existence  or  non-existence  of  pathological 
conditions.  When  the  instrument  is  used  in  such  a  manner 
that  the  anterior  focus  of  the  observed  eye  approximately 
coincides  with  the  optical  center  of  the  lens  turned  up  in  the  lens 
battery,  with  relaxation  of  the  observer's  accomm.odation,  due 
allowance  being  made  for  the  observer's  ametropia  if  such  exists, 
a  very  quick  and  approximate  estimate  of  the  refractive  condi- 
tion may  be  obtained  by  an  experienced  operator.  Under  the 
above  conditions  the  minimum  of  concave  and  the  maximum 
of  convex  lens  needed  in  order  to  see  the  veins  and  arteries 
at  a  point  some  little  distance  from  the  optic  disc  and  approach- 
ing the  macula  from  the  superior  and  inferior  regions  will  afford 
an  approximate  estimate  of  refractive  conditions.     This,  with  ex- 


Course  No.  14 
Page  16 

perience,  is  of  considerable  assistance  in  the  subsequent  saving  of 
time  in  other  objective  determinations. 

The  fundamental  principle  involved  in  static  retinoscopy 
is  conjugacy  of  foci;  that  is  to  say,  a  point  upon  the  retina 
under  observation  and  the  nodal  point  of  the  observer's  eye 
when  neutralization  of  shadow  motion  occurs  should  bear  the 
relations  of  object  and  image  points  similar  to  those  exhibited 
by  any  convex  lens  system.  It  is  not  desirable  at  this  point 
to  go  fully  into  the  theory  and  practice  of  skiametry,  but  rather 
to  simply  call  attention  to  the  fact  that  under  ideal  conditions, 
with  proper  relaxation  of  the  patient's  accommodation,  proper 
positions  of  visual  axis  with  respect  to  the  line  of  observation 
and  examination  and  accurate  centering  of  optic  media,  perfect 
neutralization  of  skiametric  shadow  motion  should  be  possible; 
this  method  should  therefore  afford  a  means,  par  excellence,  of 
determining  objectively,  and  hence,  scientifically  accurately, 
the  patient's  far  point.  But  these  ideal  conditions  rarely  exist: 
there  are  certain  possibilities  of  error  in  skiascopic  tests  which 
give  rise  to  disagreements  between  such  determinations  and 
those  made  under  subjective  tests. 

We  have  in  another  treatise  {Physiological  Optics)  discussed 
certain'factors  which  may  influence  determinations  upon  far-points 
based  upon  visual  acuity  tests;  we  shall  briefly  enumerate  and 
discuss  at  this  point  some  of  the  reasons  why  static  skiametric 
tests  as  carried  out  in  the  customary  manner  in  our  consulting 
rooms  may  be  inaccurate  or  incorrect  in  the  sense  that  such 
findings  may  rather  materially  disagree  with  subjective  findings. 
The  element  of  infallibility,  it  is  always  to  be  remembered, 
does  not  attach  itself  to  any  one  single  method  or  test,  hence  a 
comparison  of  all  ocular  data  and  a  modification  in  the  light 
of  the  evidence  furnished  by  all  tests  upon  the  various  ocular 
functions  is  demanded  in  the  final  binocular  fittings. 

Ciliary    Relaxation' — -Fixation    Definite    But    Passive 

(i)  If  the  patient  vaguely  looks  into  space,  without  the 
assistance  of  some  definite  and  partially  visable  fixation  point, 
his  gaze  is  more  than  likely  uncertain  in  direction  as  well  as 
position  in  space.  Theoretically  —  and  practically  if  ideal 
conditions  could  be  obtained  —  an  indefinite  fixation  into  space 
is  desirable.  As  a  matter  of  fact,  such  indefinite  fixation  into 
non-illuminated  space  is  a  most  difficult  procedure,  with  the 
result  that  the  patient,  stimulated  by  the  natural  desire  to  see, 
will  grope  for  some  object  or  point  sufficiently  luminous  to  be 
seen  and  only  too  often  may  be  actually  detected,  by  virtue  ot 
the  erratic  action  of  shadows,  fixing  a  near  object,  very  often 
the  operator  himself.  This  objection,  per  se,  may  be  overcome 
by  using  the  illuminated  one  hundred  foot  letter  or  letters  at 
twenty  or  more  feet;  if  these  are  not  visible  the  form  of  the  chart 
as  a  whole  or  the  frame  in  which  it  lies  will  generally  be  so  in 


Course  No.  14 
Page  17 

the  initial  examination  and  it"  not,  it  is  a  matter  of  no  conse- 
quence since  the  insertion  of  lenses,  which  approximate  in  part 
tne  necessary  correction,  will  make  such  fixation  and  vision 
possible.  To  insure  this  fixation  during  the  process  of  objective 
refraction  the  patient  may  be  asked  to  read  the  letters  and  tell 
whether  they  are  more  or  less  distinct  as  various  lens  changes 
are  made  by  the  operator  and  so  forth.  The  great  criterion 
in  static  methods  is  ciliary  relaxation.  Hence  monocular  fixa- 
tion must  be  definite  (at  a  point  twenty  or  more  feet  away), 
but  passive. 

Various  schemes  have  been  advocated  in  order  to  assure 
such  relaxation.  One  such  device  used  by  the  writer,  and,  as 
far  as  known,  original  with  him,  consists  in  turning  up  in  the  lens 
battery  of  the  optometer  or  introducing  into  the  trial  frame 
sufficient  lens  power  to  considerably  overcorrect  and  cause 
opposite  retinoscopic  motion  to  that  initially  discovered  when 
only  working  distance  lenses  are  inserted.  The  procedure  is  to 
then  slowly  reduce  lenticular  power  until  the  maximum  plus  or 
minimum  minus  just  before  reversal  of  shadow  occurs  is  reached. 
The  writer  is  satisfied  that  higher  degrees  of  hyperopia  will 
often  be  disclosed  under  such  modus  operandi.  Another  method 
suggested,  but  which  the  writer  does  not  advocate,  is  the  putting 
of  a  strong  fogging  lens  together  with  a  four  or  five  diopter 
prism  base  in  over  the  eye  not  being  tested.  The  theory  is  that 
the  fogging  lens  will  blur  to  such  an  extent  as  to  eliminate  the 
action  ot  this  eye  when  testing  its  mate,  while  the  prism,  base 
in,  will  relax  the  ciliary  through  the  relation  of  accommodation 
to  convergence.  It  is  very  doubtful  if  such  a  theory  is  correct; 
to  the  best  of  our  knowledge  inhibition  of  innervation  to  the 
interni  may  be  accomplished  through  inhibition  of  the  third 
nerve  innervation  to  the  ciliary,  but  the  process  does  not  appear 
to  be  reversible. 

Retinal  Sensitiveness  to  Light 

(2)  Retinae  unduly  sensitive  to  light  may  cause,  under 
the  influence  of  the  light  thrown  into  the  patient's  eyes,  a  tem- 
porary irritation  that  will  produce  a  spasm  of  the  ciliary.  Such 
reflex  actions  may  be  induced  to  relax  by  dimming  the  source 
of  light  used  in  retinoscopic  work.  Very  often  satisfactory 
results  can  be  obtained  by  the  use  of  the  self-luminous  instrument 
in  which  the  luminosity  can  be  controlled  through  a  resistance. 
Cases  arise  in  which  lacrymation  is  excessive  and  photophobia 
pronounced  and  in  which  the  patient  winces  and  squints  when 
the  light  is  thrown  into  the  eyes.  Under  such  conditions  one 
must  make  his  findings  ad  interim  —  waiting  a  few  moments, 
then  quickly  noting  the  direction  of  shadow  and  making  the 
necessary  lens  changes  until  neutralization  has  been  obtained. 
Or  the  subjective  findings  may  very  properly  constitute  the  sole 


Course   No.  14 
Page  18 

findings   under   such   conditions;     frequently    ciliary    relaxation 
is  much  more  complete  under  fogging  methods. 

Irregular  and  Peripheral  Refraction 

(3)  The  corneal  curvatures  and  those  of  other  refractive 
surfaces  may  not  be  truly  spherical  and  they  may  not  be  prop- 
erly centered.  As  a  result  irregular  refraction  may  be  suffi- 
ciently marked  as  to  cause  inability  to  accurately  locate  the 
point  of  retinoscopic  neutralization.  The  "visual  zone"  is  the 
portion  to  which  attention  should  be  directed;  irregularities, 
neutralization  of  shadows  and  even  reversals  of  motion  may 
occur  in  the  peripheral  regions  in  fairly  large  pupils  due  to 
aberration  and  other  effects.  These  are  at  times  confusing  and 
annoying.  Very  often  thin,  colorless  ribbons,  approaching 
in  form  the  band  peculiar  to  astigmatism,  may  arise  which  are 
due  to  irregularities  in  various  dioptric  surfaces  or  media;  gen- 
erally these  fail  to  prove  out  in  subjective  testings. 

Macular  vs.  Non-Macular  Refraction 

(4)  One  of  the  chief  sources  of  error  and  discrepancy  in 
retinoscopic  work  is  the  fact  that  most  skiascopists  do  not  test 
the  part  of  the  retina  which  is  the  conjugate  of  the  point  pas- 
sively fixed:  that  is,  the  refraction  is  not  determined  along 
the  visual  axis.  When  using  the  subjective  method  the  patient 
views  in  turn  each  of  the  letters:  an  image  ot  these  letters,  one 
at  a  time,  is  formed  on  the  fovea  centralis.  In  our  ordinary 
methods  of  skiametry  we  produce  a  spot  of  light  (image  of  our 
light  source)  upon  the  patient's  retina  at  a  point  which  is  several 
degrees  from  the  fovea  centralis.  We  may  at  best,  under  average 
conditions,  be  conducting  our  investigations  along  the  optic 
axis,  although  this  is  uncertain  since  the  position  of  the  optic 
axis  with  respect  to  the  visual  axis  is  a  variable  quantity  de- 
pending upon  the  ametropia  present,  for  the  two  axes  may 
coincide  in  certain  degrees  of  myopia  and  we  should  then  be 
working  along  neither  optic  nor  visual  axes.  If,  as  is  quite 
commonly  done,  the  patient's  gaze  as  to  his  right  eye  is  directed 
over  the  operator's  right  shoulder  and  over  his  left  for  the 
left  eye,  the  image  from  the  operator's  mirror  may  fall  at  or 
near  the  optic  disc,  as  is  evidenced  by  the  character  of  the 
reflexes  obtained  at  times. 

Certainly  optic  discs,  as  to  contour,  peripheral  elevation  or 
depression  and  so  forth,  are  as  unlike  as  the  faces  of  their  owners. 
And,  furthermore,  one  cannot  assume  a  uniformly  curved  or 
spherical  retinal  surface;  the  fovea  is  known  to  be  a  slight  de- 
pression in  the  macular  area;  hence  objective  findings  may 
differ  considerably  when  the  light  spot  upon  the  retina  falls 
at  or  remote  from  the  fovea.     Our  knowledge  of  the  fact  that 


Course   No.  14 
Page  19 

one  millimeter  change  in  axial  depth  of  an  eye  corresponds 
practically  to  a  change  of  three  diopters  in  refractive  power  would 
mdicate  the  marked  effects  which  slight  differences  in  level 
between  two  retinal  points  made  conjugate,  in  turn,  to  the 
observer's  nodal  point  may  produce.  The  vital  point  is,  then, 
that  the  skiascopic  findings  are  not  ordinarily  made  along  the 
visual  axis  and  hence  many  irregularities,  such  as  certain  cases 
of  scissor  movement  for  example,  may  arise  and  disagreements 
between  objective  and  subjective  methods  result  because  of 
lack  of  proper  scientific  precautions  in  knowing  the  conditions 
under  which  each  is  carried  out. 

John  C.  Eberhardt  has  devised  a  simple  and  ingenious 
method  of  testing  very  close  to  the  fovea  centralis  and  the  writer 
is  pleased  to  say  from  experience  that  he  has  found  it  most 
serviceable.  The  "macular  reflectoscope"  as  constructed  by 
the  inventor  consists  of  a  stand  placed,  say  forty  inches  from  the 
patient  and  carries  two  mirrors.  The  device  is  diagrammatically 
shown  as  a  horizontal  cross-sectional  cut  in  Figure  i. 


-e ^ — K3 

A  1)  R     O 

Figure  i. — Diagrammatic  Scheme  for  the  Use  of  the  Macular 
Reflectoscope. 


The  macular  reflectoscope  is  represented  at  D  and  consists  of  two 
parallel,  plane  mirrors,  L  and  A^  so  placed  before  the  eye  of  the 
person  being  examined  as  10  enable  an  iluiminated  eighty  or  one 
hundred  foot  letter  {B  in  the  figure)  to  be  seen  or  at  least  fixed 
upon  by  the  eye.  A,  in  its  primary  position  by  virtue  of  the 
double  reflection  of  light  by  the  mirrors  L  and  N  placed  at  an 
angle  of  about  forty-five  degrees  with  the  line  of  sight.  The 
double  mirror  device  causes  a  lateral  shifting  of  the  letter  or 
letters  viewed;  a  single  ray  of  light  from  the  illuminated  letter 
(5)  to  the  macula  (A/)  or  fovea  centralis  is  shown  as  B-L-N-M. 
The  operator,  0,  with  retinoscope  at  /?,  may  then  proceed  to 
the  skiametric  refraction  of  the  eye  in  a  direction  approximating 
the  direct  line  of  sight.  By  this  device  the  possibility  of  incor- 
rect findings  will  be  reduced  to  a  minimum  if,  by  the  use  of 
mirrors  as  described,  we  test  close  to  the  visual  axis. 


Course  No.  14 
Page  20 

The  writer  uses  the  macular  reflectoscope  attached  to  the 
rod  of  his  phoro-optometer  by  means  of  a  special  sleeve  sliding 
along  the  rod  ordinarily  attached  to  the  instrument  and  em- 
ployed for  carrying  the  reading  and  near  muscle-test  cards. 
This  sleeve  carries  a  screw  permitting  of  its  rigid  clamping; 
through  a  socket  at  the  side  of  this  movable  sleeve  runs  the  rod 
carrying  the  mirrors.  This  gives  practically  every  motion  as 
to  angle  and  height  of  mirrors  desired  and  allows  of  its  ready 


Figure  2. — Showing  the  Macular  Refltctoscope  in  Use. 


attachment  to  or  removal  from  the  optometer  or  can  be  swung 
by  means  of  the  rod  out  of  the  way  when  not  in  use.  It  can 
likewise  be  placed  as  near  to  or  as  far  from  the  patient  as  desired 
(up  to  twenty-six  inches  approximately),  so  that  when  +1.5  D.  S. 
is  used  as  a  working  distance  lens  the  observer's  retinoscope 
is  stationed  just  back  of  one  of  the  mirrors.  This  or  any  other 
scheme  similar  to  the  macular  reflectoscope  can  also  be  used 
without  ;trouble  when  a  chart  over  the  patient's  head  and  a 
mirror  at  ten  or  so  feet  away  are  used  in  the  testing  room. 
Figure  1  shows  a  simple  arrangement  used  by  the  writer  for 
demonstrating  the  method.  Figure  3  is  a  reproduced  photo- 
graph of  a  macular  reflectoscope  as  attached  to  the  rod  of  the 
phoro-optometer  and  shows  how  this  valuable  device  can  be 
used  in  conjunction  with  such  an  instrument. 


Course  No.  14 
Page  21 


Figure  3. — Macular  Reflectoscope  Attached  to  the  Phoro-optometer.  j  ^ 


A  very  splendid  instrument  involving  these  and  other 
refinements  has  been  devised  by  Dr.  Armbruster  of  Denver, 
Colorado. 

In  passing  it  may  be  stated  that  dynamic  skiametry, whether 
or  not  it  is  accepted  as  being  wholly  correct  in  other  respects 
in  theory  and  practice,  obviates  nearly  all  of  the  difficulties 
which  have  been  rehearsed  in  the  preceding  paragraphs.  For 
if  a  small  card  of  printed  matter,  set  in  No.  2  or  3  Jaeger  type, 
is  attached  by  means  ot  a  clip  to  the  edge  of  the  retinoscope, 
it  will  furnish  a  series  of  very  definite  fixation  letters  which 
likewise  demand  accommodative  action  on  the  part  of  the  patient 
reading  them,  and  the  visual  line  of  both  eyes  as  examined  in 
turn  will  lie  very  close  to  the  observational  line.  Likewise, 
constricted  pupils  will  eliminate  peripherial  and  other  similar 
slight  irregularities  obtained  under  static  methods  and  the 
accommodation,  through  our  instructions  to  our  patients  to 
read  the  card,  will  be  whipped  into  action  to  its  maximum  capac- 
ity, hence  totally  eliminating  the  question  of  relaxation  of 
accommodation  as  understood  in  the  static  sense.  Further- 
more, the  eyes  will  assume  their  positions  o^  torsional  equilibrium; 
hence  the  axes  of  the  correcting  cylinders  may  be  found  some- 
what shifted  in  position  from  those  found  under  static  monocular 
methods.  But  dynamic  skiametry  introduces  the  perplexing 
problem  of  the  correlation  between  convergence  and  the  accom- 
modation and  the  question  as  to  the  validity  of  the  findings, 
under  some  possible  modifications,  for  distant  as  well  as  near 
visual  use  or  as  a  reading  correction  only. 


Course   No.  14 
Page  22 

Chapter  III. — The  Determination  of  the  Near- 
point  and  of  the  AmpUtude  of 
Accommodation 

The    Near-point    and    the    Influence    of   Various   Factors 
Upon   Its   Determination 

Thus  far  we  have  discussed  some  of  the  methods  and  useful 
means  of  determining  the  far-point  through  various  objective 
and  subjective  methods  of  finding  a  suitable  lenticular  correc- 
tion which  would  render  infinity  and  the  retina  of  the  eye  under 
test  conjugate  points  We  have  paid  particular  attention  to 
pointing  out  some  of  the  discrepancies  which  may  arise  between 
subjective  and  objective  findings  in  monocular  tests,  but  have 
not  discussed  the  broader  and  more  vital  question  of  the  proper 
co-ordination  of  the  eyes  in  binocular  vision.  We  do  have, 
however,  both  objective  and  subjective  methods  for  the  deter- 
mination of  the  manifest  error  of  an  eye  and  by  means  of  simple 
mathematical  expressions,  taking  into  account  the  distance  of 
the  lenticular  correction  from  the  cornea,  are  able  to  calculate 
the  manifest  or  apparent  punctum  remotum.  For  those  who 
desire  there  remain  in  addition  those  determinations  upon  the 
absolute  refractive  conditions  which  are  made  through  the  use 
of  cycloplegics  in  which,  presumably,  the  absolute  punctum 
remotum  can  be  determined.  It,  therefore,  seems  scientifically 
possible  to  make  accurate  determinations  as  to  the  location 
of  the  apparent  and  of  the  absolute  far-points.  We  are  not  as 
fortunate  when  we  come  to  the  determination  of  the  near-point 
and  hence  to  the  ultimate  determination  of  the  amplitude  of 
accommodation,  which  involves  the  difference  between  the 
static  and  dynamic  refraction  of  the  eye.  But  we  have  an 
objective  method  for  determining  the  position  of  the  punctum 
proximum  as  well  as  various  test  objects  and  subjective  methods 
of  finding  its  location.  All  have  inherent  errors  and  defects. 
For  as  Tscherning  says:  "The  determination  of  the  near-point 
is  not  very  certain,  since  its  position  depends  upon  an  effort 
of  the  patient,  the  strength  of  which  may  vary  from  day  to  day." 
And  Landolt,  writing  in  that  classic  volume  entitled  The  Re- 
fraction and  Accommodation  of  the  Eye^  (which  parenthetically 
the  present  writer  wishes  some  scholarly  practitioner  would 
revise  and  some  enterprising  publisher  reprint)  says:  "If,  in 
practice,  we  seek  the  punctum  proximum,  we  wish  to  know  the 
maximum  refraction  that  an  eye  can  assume  under  the  impulse 
of  the  will  and  not  under  the  influence  of  a  cause  foreign  to  the 
organism.  This  will  being  manifested  especially  in  the  interest 
of  near  vision,  the  person  examined  should  always  be  permitted 
to  be  himself  master  of  his  desire  to  see  distinctly  and  the  judge 
as  to  the  degree  in  which  he  succeeds  in  so  doing.  In  other  words, 
we  are  dependent  in  the  determination  of  the  accommodation 
upon   the  patient's  good  nature  and  intelligence;    a  fact  which 


Course   No.  14 
Page  23 

often  deprives  the  examination  of  the  desired  accuracy.  It 
is  for  this  reason,  too,  that  there  exists  no  objective  method 
(properly  so  called)  of  obtaining  the  amplitude  of  accommodation. 
The  maximum  effort  of  accommodation  is  hard  to  obtain  from 
the  patient  unless  we  give  him  an  object  of  fixation.  But  by 
so  doing  we  return  to  the  subjective  methods.  ...  In 
order  to  know  whether  the  object  is  at  the  punctum  proximum 
we  must  have  recourse  to  the  clearness  of  the  visual  impression." 
We  do  possess,  however,  the  objective  method  devised  in  recent 
years  by  the  writer;  still  the  objection  that  Landolt  raises  is 
applicable. 

There  are  two  principles  or  methods  of  procedure  in  common 
use,  which  are  in  theory  essentially  identical,  for  determining 
the  dynamic  refraction.  We  either  seek  the  situation  of  the  near 
point  and  measure  its  distance  from  the  eye  and  take  the  inverse 
of  this  quantity  to  represent  the  total  dynamic  refraction  or 
else  we  determine  upon  that  lens  whose  refractive  power  equals 
that  of  the  eye  at  its  maximum  of  accommodation. 

I.     Determination  of  the  Situation  of  the  Near-point 

To  obtain  the  near-point,  commonly  used  test-objects  con- 
sist of  small  printed  character  or  fine  type,  or  groups  of  small 
black  dots  upon  a  white  ground  or  black  threads  on  a  white 
background  stretched  across  a  frame  constituting  an  instrument 
usually  referred  to  as  the  wire  optometer.  The  commonest 
method  in  vogue  is  to  employ  about  No.  2  Jaeger  type  (V=  .5  D.) 
and  to  approach  this  toward  the  eye,  its  mate  being  covered, 
until  the  nearest  point  is  reached  at  which  it  can  still  be  seen  or 
read,  or  in  other  words  until  it  commences  to  get  indistinct. 
A  measurement  of  this  distance  from  the  cornea  of  the  eye  is 
commonly  taken  as  the  punctum  proximum.  In  a  case  of 
emmetropia  this  distance,  when  reduced  to  diopters,  gives  the 
amplitude  of  accommodation.  This  method  in  ametropic 
cases  gives  only  the  apparent  or  available  and  not  the  true 
amplitude.  Likewise,  it  may  not  be  available  in  presbyopic 
conditions,  since  the  near-point  may  have  receded  so  far  from  the 
eye  that  fine  print  is  not  readable;  in  such  a  case,  however,  a 
convex  lens  may  be  furnished  to  assist  the  patient  and  bring 
the  near  point  to  a  measurable  discance,  finally  deducting  the 
auxiliary  lens  from  the  dioptric  value  found.  In  ametropia 
the  practitioner  will  be  saved  considerable  time  and  trouble, 
as  well  as  mental  arithmetic,  in  obtaining  the  true  amplitude 
of  accommodation  if  he  supplies  the  patient  with  the  correction 
for  the  refractive  error  statically  determined  at  infinity  first  of 
all,  since  then  presumably  the  far-point  is  at  infinity  or  approach- 
ing it  as  closely  as  conditions,  both  pathological  and  non-patho- 
logical, will  permit.  The  eye  is  then  emmetropic  or  as  nearly 
so  as  possible  and  the  procedure  in  determining  the  amplitude 
of  accommodation  is  the  same  as  that  for  emmetropia.  The 
statement   relative    to    the    giving   of   the    distance    correction 


Course   No.  14 
Page  24 

when  making  tests  by  any  method  upon  the  near  point  or  in  the 
determination  ot  the  amplitude  of  accommodation  is  worthy  of 
repetition,  since  the  absence  of  cylindrical  corrections,  especially 
if  they  are  of  any  appreciable  value,  plays  a  considerable  role 
and  almost  invariably  leads  to  incorrect  determinations  and 
conclusions. 


The  determination  of  a  correct  near-point  is  not  as  simple  in 
practice  as  in  theory.  For  the  size  of  the  test  or  type-object 
must,  in  the  first  place,  bear  a  certain  relation  to  the  visual 
acuteness  of  the  eye  under  examination.  There  are  persons 
who  possess  a  good  range  of  accommodation  who  cannot  read 
fine  print  at  any  distance  because  their  visual  acuteness  is  too 
low;  in  such  cases  larger  test-objects  must  be  used.  And,  in 
the  second  place,  as  already  pointed  out,  the  punctum  proximum 
may  be  so  far  away  as  to  render  small  test-objects  indistinguish- 
able, even  by  an  eye  whose  visual  acuity  is  normal.  This 
difficulty  is  remedied  by  the  giving  of  a  convex  lens  which  in- 
creases the  refraction  and  hence  brings  the  near-point  closer; 
this  arbitrarily  added  lens  must  ultimately  be  subtracted  from 
the  refraction  corresponding  to  the  near-point  of  the  system 
to  give  that  of  the  eye  alone.  The  first  objection,  i.  e.,  that  ot 
reduced  acuity,  must,  however,  be  an  inherent  difficulty  in  the 
determination  of  the  accommodative  amplitude  of  such  an  eye 
by  whatever  method  tested.  In  the  second  case  the  accommo- 
dative power,  either  normally  or  abnormally  depleted,  must  be 
assisted  in  order  that  the  test-object  may  be  seen.  The  question 
arises  as  to  whether  or  not,  if  different  quantities  of  assistance 
are  offered,  the  ultimate  determinations  of  the  near-points  will 
be  in  agreement.  Let  us  assume  two  cases:  (a)  suppose  the 
lens  given  to  be  -|-  10  D.  and  the  point  up  to  which  vision  remains 
clear  to  be  9  cms.  and  (b)  suppose  the  lens  given  to  be  +6  D. 
and  the  point  up  to  which  vision  remains  clear  to  be  14  cms. 
Each  of  these  cases  of  a  theoretical  nature  brings  out  the  punctum 
proximum  as  one  meter  distance  from  the  eye.  In  practice  such 
determinations  would  involve  uncertainties  or  errors  of  measure- 
ment which  would  be  vital,  since  small  distance  differences  may 
represent  considerable  refractive  differences;  but,  assuming 
such  errors  excluded,  the  two  determinations  inherently  involve 
differences  due  to  the  sizes  of  the  retinal  images  by  virtue  ot  the 
fact  that  the  same  sized  object,  when  placed  at  9  cms.  and  at 
14  cms.  respectively  from  the  eye,  subtend  different  visual 
angles  at  the  nodal  point  of  the  eye.  Hence  it  is  very  doubtful 
whether  two  such  tneoretical  cases  leading  to  the  same  result 
would,  if  tested  in  practice  under  the  conditions  named,  give 
equality.  My  experience,  which  has  been  rather  limited  in  making 
such  determinations  with  wide  ranges  of  lenticular  assistance 
offered,  has  led  me  to  the  conclusion  that  only  approximate 
agreement  is  forthcoming. 


Course  No.  14 
Page  25 

This  discussion  leads  us  to  the  really  vital  source  of  error 
in  near-point  determinations  and  that  is  this:  the  size  of  the 
retinal  image  of  the  test-object  increases  as  the  test-object  is 
approached  to  the  eye;  hence,  if  a  five  minute  visual  angle  stand- 
ard is  to  hold  in  near  as  well  as  distant  testings,  a  type  which 
fulfills  this  criterion  at  33  centimeters  from  the  eye  will,  at  a 
lesser  distance,  give  retinal  images  which  are  too  large  and  there- 
fore give  inaccurate  near-points.  Inaccurate  accommodative 
amplitudes  from  near-point  determinations  are  due,  the  writer 
believes,  to  two  factors  chiefly:  (i)  there  is  a  more  rapid 
increase  of  the  visual  angle  than  of  the  circles  of  diffusion,  hence 
the  person  under  test  is  able  to  read  at  a  point  nearer  than  that 
at  which  accommodation  is  still  being  proportionately  enforced; 
by  this  is  meant,  in  other  words,  that  the  enlarged  retinal  images, 
although  diffused,  are  mentally  interpreted  and  seen  when 
smaller  but  sharper  images  are  not,  and  (2)  the  reduction  in 
the  size  of  the  pupil  which  occurs  normally  upon  the  approach 
of  an  object  to  an  eye  and  which  in  turn  lessens  the  sizes  of  the 
circles  ot  diffusion. 

Diameters  of  the  diffusion  circles  will  be  still  further  reduced 
if  the  pupil  changes  size,  as  is  the  case  upon  the  approach  of  the 
test-object  to  the  eye.  The  size  of  the  circle  of  diffusion,  2, 
may  be  calculated  for  any  sized  diameter  pupil  of  exit,  />,  from 

d 
z  =  p 

d±a 

an  expression  in  which  a  represents  the  distance  of  the  retina 
from  the  pupil  and  d  the  distinct  image  from  the  retina  (see 
Tscherning,  Physiologic  Optics^  page  73).  If  then  the  quantities 
d  and  a  remain  constant,  as  would  be  in  the  case  ir  the  eye 
were  viewing  a  given  object  at  a  given  position,  the  circles  of 
diffusion  will  be  decreased  in  area  as  the  diameter  of  the  pupil 
contracts.  It  can  be  seen,  therefore,  that  the  factors  affecting 
the  readability  of  fine  print  at  a  point  close  to  the  eye  are  varied 
and  that  they  are  rather  interdependently  and  intricately 
related. 

The  explanations  in  which  we  have  just  indulged  afford  us 
reasons  as  to  why,  in  cases  of  high  hyperopia  or  high  hyperopic 
astigmia,  small  objects  can  be  seen  better  nearer  the  eye  than  at 
some  distance  from  it,  thus  resembling  a  condition  of  myopia. 
For  the  high  hyperope,  far  from  moving  his  book  away  from  him, 
brings  it,  on  the  contrary,  very  close  to  his  eyes  —  much  nearer 
than^his  real  punctum  proximum  —  in  such  a  way  as  to  simulate 
myopia.  This  hyperope,  so  to  speak,  "applies  his  eyes  to  the 
paper";  being  unable  to  obtain  distinct  retinal  images,  he 
obtains  as  large  ones  as  possible.  His  circles  of  diffusion  are 
not  an  obstacle  to  him,  for,  in  the  first  place,  their  diameter, 
generally  limited  by  the  narrowness  of  the  pupils,  increases  only 
in  proportion    to   the  square   root  of  the  decrease  in  distance, 


Course   No.  14 
Page  26 

while  the  size  of  the  image  increases  proportionately  to  this 
decrease  itselt.  And,  in  the  second  place,  there  exists  in  his 
case  (high  hyperopia)  a  singular  aptitude  for  analyzing  imperfect 
retinal  images  and  making  out  the  form  of  the  object  in  spite 
of  the  diffusion  circles  of  which  its  image  is  composed. 

There  is  still  another  and  important  factor  affecting  the 
readability  of  fine  print  at  a  point  close  to  the  eye  and,  therefore, 
the  determination  of  the  punctum  proximum.  We  have  already 
mentioned  the  effect  of  the  increase  of  the  visual  angle  and  hence 
of  the  retinal  image  as  a  type  which  fulfills  the  proper  visual  acuity 
standard  at  thirteen  inches  is  approached  toward  the  eye  under 
test,  and  we  have  also  discussed  the  effect  of  the  decrease  of 
pupillary  area  and  of  the  diffusion  circles  upon  the  retinal 
images.  All  of  these  sources  of  error  tend  in  one  direction  and 
that  is  to  indicate  a  punctum  proximum  closer  to  the  eye  and 
hence  a  greater  equivalent  amplitude  of  the  eye  under  test 
than  it  in  reality  possesses.  There  is  in  addition  the  effect  of 
closing  the  lids  and  thus  narrowing  the  palpebral  fissure;  this 
virtually  amounts  to  a  restriction  in  the  size  of  the  pupil  of  an 
eye  which  may  have  already  contracted  considerably  as  to  the 
near-point  test  is  being  made.  This  narrowing  of  the  pupillary 
opening  by  lid  action  is  particularly  potent  and  active  in  the 
case  of  high  astigmats  or,  in  general,  for  those  eyes  possessing 
reasonably  large  ametropic  errors.  There  will  thus  result  an 
effective  decrease  in  pupillary  size  analogous  to  the  effects  pro- 
duced by  a  stenopaic  disc  with  the  consequent  reduction  in  the 
size  of  the  diffusion  circles  and  the  fine  type  when  moved  closer 
and  closer  to  the  eye.  In  astigmatic  errors  such  a  lid  action 
would  enable  accommodation  to  be  exerted  to  an  extent  suitable 
for  the  horizontal  meridian;  it  is  possible,  therefore,  that  this 
stenopaic  slit  action  will  either  augment  or  decrease  the  apparent 
distance  of  the  near-point  from  the  eye.  If,  therefore,  one  is 
certain  of  his  cylindrical  correction  it  seems  a  wise  procedure 
to  insert  it  before  the  patient's  eye  before  making  any  near- 
point  determinations,  for  it  can  be  shown  that  the  sizes  of  the 
diffusion  focal  lines  and  ellipses  vary  in  size  directly  as  the 
pupillary  aperture  and  as  their  respective  distances  from  the 
retina. 

The  reader  will,  therefore,  appreciate  the  fact  that  the 
writer  is  not  very  enthusiastic  about  the  value  of  near-point 
determinations  as  ordinarily  made  with  a  tape  line  and  a  tew 
lines  of  fine  test-type.  Of  course,  in  the  average  run  of  cases 
it  serves  well  enough  in  that  Nature  has  been  reasonably  generous 
to  mankind  in  general  and  been  sufficiently  democratic  to  give 
the  majority  of  people  at  any  certain,  specified  age  about  the 
same  modicum  of  accommodation.  Hence,  after  perscribing  the 
distance  correction  for  the  specified  age  as  given  by  the  usual 
"Punctum  Proximum  —  Age"  chart,  one  might  pass  the  case  up 
as  accommodatively  satisfactory  and  probably,  in   the  light  ot 


Course   No.  14 
Page  27 

the  percentages  of  persons  of  all  ages  who  exhibit  normal  as 
opposed  to  subnormal  or  abnormal  accommodative  conditions, 
satisfy  the  majority  of  his  patients  and  give  them  ocular  comfort 
and  efficiency  if  other  details  in  the  ocular  examination  have 
been  carefully  determined  and  regarded.  But  subnormal  and 
paretic  accommodation  or  premature  presbyopia  is  not  as  rare 
as  it  was  thought  to  be  years  ago  and  in  some  of  the  really 
intricate  and  difficult  cases  near-point  determination  will  often 
lead  one  into  error.  Some  such  cases  with  various  determina- 
tions upon  the  ocular  functions  follow  in  succeeding  paragraphs 
in  this  chapter. 

These  same  objections  are  in  a  measure  applicable  to  our 
ordinary  methods  of  determining  the  amplitude  of  accommoda- 
tion in  presbyopia  by  finding  the  nearest  point  at  which  No.  2 
Jaeger  type  (usually)  can  be  read  after  an  arbitrary  amount  of 
convex  lens  assistance  has  been  given.  There  must,  of  course, 
be  ultimately  subtracted  from  the  near-point  equivalence  in 
diopters  the  amount  of  convex  lens  offered  in  assistance.  We 
find  in  like  manner  the  reading  far-point  and  thus  determine 
the  range  of  reading  amplitude.  But  it  can  be  said  by  way 
of  support  of  our  ordinary  methods  of  ministering  to  presbyopic 
conditions  that  the  factors  which  are  so  effectual  in  vitiating  near 
point  determinations  are  not  as  effective  and  hence  important  in 
such  presbyopic  determinations  since,  for  one  reason,  the  near 
point  has  receded  from  the  eye  hence  making  it  impossible  to 
draw  the  print  as  close  to  the  eye  as  can  be  accomplished  by  young 
people.  Furthermore,  such  presbyopic  conditions  are  not  due 
to  a  fundamental  weakening  of  the  ciliary  muscles  but  merely 
to  an  increasing  hardness  or  lack  of  elasticity  of  the  lenticular 
substance  and  no  efforts,  however  strong,  on  the  part  of  the 
ciliary  muscle  can  increase  the  curvature  of  the  crystalline  lens 
beyond  a  certain  point.  We  must  differentiate,  therefore, 
between  normal  and  abnormal  accommodative  changes  or 
between  proper  and  premature  presbyopia.  Our  only  objective 
methods  for  the  determination  of  presbyopic  corrections  are 
dynamic  skiametry  and  the  writer's  objective  method  of  deter- 
mining the  range  and  amplitude  of  accommodation.  Certainly 
extreme  accuracy  cannot  be  claimed  for  either  method.  We 
can  by  its  usage,  however,  determine  the  accommodative  needs 
of  a  pair  of  eyes  at  any  given  reading  distance,  modified  pre- 
sumably by  the  demands  for  harmonious  correlation  between 
accommodation  and  convergence.  Likewise,  the  amount  of 
reserve  accommodation  which  should  be  preserved,  ranging 
from  a  quarter  to  a  half  of  the  total  amount  available,  varies 
with  practitioners  and  should,  indeed,  vary  in  the  light  of  the 
determinations  which  should  be  made  upon  the  convergence  as 
associated  with  the  accommodation.  We  are  sadly  in  need  of 
methods  as  applicable  and  as  scientific  in  presbyopic  cases  as 
those  we  possess  in  general   ametropic  and  muscular  testings. 


Course  No.  14 
Page  28 

The  writer  on  Amplitude  of  Accommodation  in  the  American 
Encyclopedia  of  Ophthalmology  says:  "The  near-point  is  the 
distance  at  which  an  object  can  be  seen  distinctly  with  the 
greatest  curvature  of  the  lens.  In  practice,  fine  print,  (Jaeger 
No.  I  or  the  corresponding  Snellen  type)  is  used  to  determine 
the  near-point.  These  tables  are  brought  near  to  the  eye  until 
the  print  appears  blurred.  The  size  of  the  object  and  the  width 
of  the  pupil  are  important  factors  to  be  considered  and  as  the 
above  method  deals  with  a  narrow  visual  field  only,  not  the  real 
near  point  but  a  "pseudo"  near  point  is  obtained,  which,  in 
general,  is  nearer  to  the  eye  than  the  true  punctum  proximum." 
Certainly,  then,  in  the  light  of  all  this  evidence  it  is  only  proper 
that  the  practitioner  record  his  results  by  such  methods  as 
"pseudo"  near-points  and  not  true  near-points  and  many  of  the 
statements  in  our  text-books  upon  the  determination  of  the 
near  point  should  be  revised  in  accordance   therewith. 

The  position  of  the  near-point  may  be  found  by  employing 
some  method  depending  upon  Scheiner's  experiment  The 
eye,  gazing  at  a  small  point  through  two  small  holes  close  to- 
gether in  a  disc,  will  see  the  point  fixed  as  double  if  the  eye  is 
not  sharply  focused  and  single  if  it  is.  With  the  least  error  in 
focusing  two  points  will  be  seen  instead  of  one.  This  and 
Young's  optometer  are  probably  among  the  best  devices  for 
obtaining  true  near-points,  but  they  are  impracticable  for  use 
with  the  average  patient  and  involve  a  co-operation  between 
patient  and  practitioner  which  is  difficult  of  obtainment.  In 
fact,  as  noted  once  before,  any  method  of  determining  near- 
points  or  amplitudes  of  accommodation  is  dependent  upon  the 
will  and  good  nature  as  well  as  intelligence  of  the  patient.  The 
most  satisfactory  subjective  tests  must  involve,  after  all  is  said 
and  done,  the  reading  of  printed  words,  some  of  which  should 
be  familiar  and  some  unfamiliar  to  the  person  under  test. 

II.     Determination  of  the  Near-point  by  Ascertaining   the 

Lens  Whose  Refractive  Power  Equals  That  of  the 

Eye  at  its  Maximum  Accommodation,  the 

Tests  Being  Made  Monocularly  at 

Twenty  Feet 

A  simple  lens  is  sufficient  to  determine  the  refraction  of 
the  eye  at  the  moment  of  its  maximum  accommodation.  Thus, 
as  Landolt  says,  "for  a  person  whose  punctum  proximum  is 
situated  at  a  finite  distance,  it  amounts  to  the  same  thing  whether 
he  looks  at  an  infinitely  distant  object  through  a  concave  lens" 
or,  without  a  lens,  at  an  object  situated  at  a  distance  equal  to 
the  focal  length  of  the  lens  used.  A  concave  lens  gives  to 
parallel  rays  of  light  the  divergence  that  they  would  have  if 
they  came  from  the  point  represented  by  the  focal  length  of  the 
lens.  To  see  at  16.66  cms.  a  refractive  change  of  accommodation 
of  6   D.   is   demanded   of  the   emmetrope.     In   order,   in    turn, 


Course  No.  14 
Page  29 

to  see  distinctly  at  a  distance  through  a  concave  lens  of  6  D. 
power  an  excess  of  positive  refraction  or  an  accommodative 
change  amounting  to  6  D.  is  evidently  required  in  order  to 
neutralize  the  negative  6  D.  of  the  concave  lens.  Hence, 
theoretically  at  least,  we  need  only  to  seek  the  strongest  con- 
cave lens  (equivalent  to  the  difference  between  the  strongest 
plus  and  the  strongest  minus,  or  weakest  minus  and  strongest 
minus,  which  are  dependent  upon  the  ametropia  present)"through 
which  an  eye  still  sees  distinctly  at  a  long  distance  and  this  lens 
will  give  the  maximum  of  refraction  of  which  the  eye  is  sus- 
ceptible." The  quoted  portion  of  this  last  sentence  is  from 
Landolt:  the  italics  are  due  to  the  writer  for  the  purpose  of 
calling  attention  to  the  fact  that  the  indetiniteness  of  "seeing 
distinctly  at  a  long  distance"  and  just  what  should  be  the 
standards  of  test  in  such  methods  constitute  some  of  the  chief 
drawbacks  to  the  practicability  of  employing  concave  lens  for 
determining  amplitudes  of  accommodation  under  the  conditions 
specified. 

Let  us  consider  a  few  simple  cases  and  then  pass  on  to  a 
further  discussion  of  the  merits  and  demerits  of  such  procedure. 
For  an  emmetrope  with  eye  adapted  to  parallel  light,  one  eye 
being  occluded,  the  strongest  concave  glass  expresses  directly 
the  amplitude  of  accommodation.  An  emmetrope  seeing  dis- 
tinctly at  a  distance  with  a  —  8  D.  lens  before  his  eye  has  an 
amplitude,  according  to  this  method  of  determining  it,  of  8D. 
For  myopia,  the  strongest  concave  lens  with  which  he  sees  at  a 
distance  still  gives  the  position  of  the  punctum  proximum  and 
the  refraction  corresponding  to  the  maximum  accommodation. 
In  order  to  find  the  amplitude  of  accommodation,  however,  the 
static  myopia  must  be  known.  The  amplitude  of  accommoda- 
tion is,  therefore,  expressible  as  the  difference  between  the 
strongest  and  weakest  minus  lenses  with  which  distance  can 
be  clearly  seen.  A  myope  of  2  D.,  being  able  to  overcome  a 
—  8  D.  lens,  would  have  6  D.  of  accommodation.  A  hyperope 
who  sees  at  a  distance  with  a  concave  lens  also  has  his  punctum 
proximum  at  the  focus  of  the  latter  and  under  this  condition  the 
refraction  of  his  eye  is  likewise  equal  to  the  refractive  power 
of  the  concave  lens  that  it  neutralizes.  But  a  hyperopic  eye 
may  be  regarded  as  an  insufficiency  of  refractive  power,  hence 
accommodative  action  must  in  reality  supply  this  deficit  in 
addition  to  the  concave  lens  overcome.  If  the  degree  of  hyper- 
opia be  1  D.  and  the  concave  lens  through  which  distance  is 
still  clearly  seen  —6  D.,  then  the  amplitude  of  accommodation 
is  8  D.  And,  again,  it  may  happen  that  the  maximum  effort 
of  accommodation  does  not  suffice  to  wholly  neutralize  the 
hyperopia.  If  the  strongest  convex  lens  gives  the  measure 
of  the  static  refraction  of  the  eye,  the  weakest  convex  lens 
indicates  the  maximum  refraction  obtained  with  the  aid  of  the 
accommodation.  Hence  the  difference  between  the  two  is  the 
amplitude     of    accommodation.     To    recapitulate,     then,     the 


Course   No.  14 
Page  30 

strongest  concave  or  weakest  convex  lens  with  which  an  eye 
can  see  at  a  distance  gives  the  refraction  of  that  eye  when 
adapted  to  its  punctum  proximum.  The  sign  of  the  lens  must 
be  changed,  however,  since  concave  indicates  positive  and  con- 
vex shows  negative  refraction.  In  emmetropia  the  concave  lens 
expresses  directly  the  amplitude  of  accommodation.  In  myopia 
we  must  subtract  therefrom  the  value  of  the  lens  which  corrects 
the  ametropia.  And  in  hyperopia  the  amplitude  of  accommoda- 
tion is  given  by  the  algebraic  difference  between  the  dioptric 
value  of  the  strongest  concave  or  weakest  convex  and  that  of 
the  maximum  correcting,  or  convex,  lens. 

There  are  several  vital  objections  to  this  procedure,  however, 
(i)  The  visual  acuteness  is  considerably  diminished  by  the  use 
of  concave  lenses  which  diminish  the  size  of  the  retinal  images, 
for  it  is  difficult  for  experienced  observers  to  judge  accurately 
as  to  whether  their  visual  acuteness  suffers  from  a  lack  of  clear- 
ness or  from  the  diminution  in  the  sizes  of  the  images.  (2)  The 
term  "distinct  vision  at  distance"  is  very  indefinite.  If  the 
normal  acuity  line  is  taken  as  a  standard,  /'.  e.,  when  a  corrected 
eye  can  really  develop  this  acuity,  the  effect  of  concave  lenses 
upon  the  retinal  images  thereby  produced  makes  it  rapidly 
unreadable.  (3)  It  is  difficult  to  get  an  eye  to  put  forth  its 
maximum  effort  of  accommodation  when  looking  at  a  distance. 
Accommodation  is  not  invited  nor  encouraged  as  it  is  by  an 
object  approached  progressively  to  the  eye.  (4)  It  is  a  test 
upon  a  function  made  in  a  manner  which  demands  that  it  be 
brought  into  play  under  conditions  contrary  to  those  set  for 
it  by  nature.  The  minimum  accommodative  condition  of  an 
eye  is  always  demanded  and  generally  obtains  when  viewing 
distant  objects.  It  is  certainly  true  that  the  amplitude  of 
accommodation  obtained  by  this  method  is  less  than  that 
furnished  (apparently)  by  a  direct  determination  of  the  near- 
point  in  the  manner  discussed  in  previous  paragraphs.  The 
reasons  are  very  obvious,  for  the  factors,  such  as  increase  in 
size  of  retinal  images,  which  are  likely  to  cause  a  pseudo  near- 
point  which  is  too  close  to  the  eye,  are  exactly  reversed  in  their 
character,  i.e.,  a.  decrease  in  the  size  of  retinal  images  for  example, 
when  using  concave  lenses  and  viewing  a  distant  test-object. 
It  seems  not  at  all  improbable  that  an  average  of  the  two  ampli- 
tudes obtained  by  these  two  methods  will  give,  in  the  general 
run  of  cases,  a  fairly  true  estimate  of  the  real  amplitude  of 
accommodation.  This  "concave-at-distance"  method,  as  we 
are  pleased  to  call  it,  however,  inaccurate  as  it  may  be,  is 
probably  a  much  safer  method  to  pursue  than  the  near  point 
determination  by  fine  print  and  it  affords  valuable  corroborative 
evidence  in  tests  made  by  still  another  method  yet  to  be  discussed. 

The  writer  uses  this  method  at  times  and  proceeds  in  general 
upon  the  following  basis.  First  of  all  the  statically  determined 
monocular  correction  is  inserted  in  the  trial  frame,  one  eve  is 


Course   No.  14 
Page  31 

occluded  and  the  other  put  under  test.  Incidentally,  the  writer 
in  private  practice  uses  the  phoro-optometer,  (carrying  the 
lens  battery)  which  enables  him  to  make  rapid  changes  and 
complete  the  tests  by  this  "concave-at-distance"  method  of 
determining  the  amplitude  in  short  order.  If  the  acuity  is 
normal  under  the  correction  offered,  the  writer  usually  selects 
the  V  =  8/io  (to  V  =  6/io)  line  as  a  basis  for  the  test-object  to 
afford  distinct  distant  vision,  the  patient  being  seated  20  feet 
from  the  chart.  The  procedure  is  then  to  find  the  maximum 
minus  through  which  these  test-objects  can  be  seen  in  cases  of 
hyperopia  and  so  on  as  outlined  in  the  preceding  paragraphs. 
Some  very  interesting  observations  can  often  be  made  during 
these  tests.  In  some  instances  the  accommodative  action  is 
sluggish  or  non-responsive,  requiring  time  to  respond,  while 
in  other  cases  it  is  very  responsive  but  when  once  pulled  out 
to  its  full  capacity  seems  to  be  unable  to  withstand  the  demands 
for  but  brief  periods  of  time.  We  shall  have  occasion  to  refer 
to  such  conditions  under  the  topic  of  Subnormal  or  Difficult 
Accommodation. 

Illustrative  Case.  In  cases  of  paretic  or  subnormal  accom- 
modation valuable  information  is  often  quickly  obtained.  To 
illustrate:  take  the  following  case:  —  A  girl,  aged  8  years,  just 
recovering  from  measles,  is  round  shouldered  and  has,  when 
we  give  her  a  book  to  read,  a  decided  tendency  to  thrust  her 
neck  and  chin  forward;  this  tendency  has  apparently  devel- 
oped due  to  the  fact  that  the  mother  has  tried  to  induce  the 
child  to  hold  her  book  away  from  her  face  while  reading;  the 
child  has  apparently  very  logically  concluded  to  come  to  the 
book  if  the  book  was  not  allowed  to  come  to  her.  Subjectively 
we  found  O.  U.+0.50  D.  8.3+0.50  cyl.  ax,  90,  giving  V  +  20  20. 
Monocularly  +1  D.  S.^+O-fO  cyl.  ax.  90  blurred  distant 
vision  badly.  Through  a  —.5  D.  S.  0  +  -5  ax.  90  or  through 
—  .5  D.S.  alone  she  was  hardly  able  to  see  the  50  foot  letters  or 
even  distinguish  relatively  small  objects  in  the  room.  Her 
total  amplitude  according  to  this  test  is,  therefore,  1.5  D.  She 
could  not  read  No.  2  Jaeger  type,  wearing  her  distance  correc- 
tion, at  13  inches,  but  could  read  it  when  this  type  was  pulled 
up  to  within  four  or  five  inches  of  her  eye.  This  is  a  beautiful 
example  of  pseudo  punctum  proximum  and  of  the  erroneous 
conclusion  to  which  it  would  lead  a  practitioner.  Her  accommo- 
dation was,  then,  approximately  1.5  D.;  the  accommodative 
demands  may  have  been  innervationally  met,  but  certainly 
lenticular  action  did  not  result,  yet  it  is  to  be  doubted  if  the 
necessary  innervation  at  the  near-points  at  which  she  read  was 
delivered  to  anything  like  the  full  and  normal  amount.  She 
was  presumably  possessed  of  no  more  refractive  changes  through 
accommodative  effort  at  5  inches  than  she  was  at  13  inches, 
but  the  decrease  ot  pupillary  size,  the  closing  of  the  eyelids  and 
the  increased  size  of  the  retinal  images  enabled  her  to  read  at  an 
abnormally  close  reading  point  and  not  at  a  normal  reading  point. 


Course   No.  14 
Page  32 

We  gave  her  +1.5  D.  S.C+0.50  cyl.  ax.  90,  O.  U.,  to  be  worn 
while  reading  and  at  near  work  during  the  first  few  days  and  to 
be  worn  as  constantly  as  possible  thereafter.  She  could  read 
No.  I  Jaeger  type  readily  at  13  inches.  She  was  likewise  referred 
to  her  family  physician  to  whom  a  report  of  her  condition  was 
made.  Today  she  is  wearing  O.  U.  +  -  D.  S.O+0.50  cyl.  ax.  90 
and  has  six  or  seven  diopters  of  accommodation. 

Ill      Determination  of  the  Near-point  and  of  the  Amplitude 

of  Accommodation  by  Ascertaining  the  Lens  Whose 

Refractive  Power  Equals    that    of  the  Eye  at 

its  Maximum  Accommodation,  the  Test 

Being  Made  Monocularly  at 

Thirteen  Inches 

This  method  is  essentially  a  modification  of  that  discussed 
in  connection  with  the  determination  of  the  punctum  proximum 
and  of  the  amplitude  of  accommodation  by  finding  the  lens 
whose  refractive  power  equals  that  of  the  eye  at  its  maximum  of 
accommodation  when  the  tests  are  made  monocularly  with 
test  letters  at  twenty  feet.  In  the  discussion  of  the  aforesaid 
method  it  was  pointed  out  that  one  of  the  most  vital  objections 
to  such  a  procedure  lies  in  the  fact  that  it  is  a  test  upon  a  func- 
tion made  in  a  manner  which  demands  that  it  be  brought  into 
action  under  conditions  which  are  not  in  accord  with  those 
under  which  it  normally   functions  and  operates. 

Accommodative  action  should  be  nil  at  twenty  feet;  it 
therefore  seems  an  illogical  procedure  to  test  its  maximum 
capacity  at  a  point  for  which  there  is  normally  demanded  its 
absolute  suppression.  This  fundamental  and  basal  principle 
in  all  ocular  investigations  is  very  clearly  and  forcibly  expressed 
by  Eberhardt  in  his  ''Dynamics  and  Economics  of  the  Binocular 
Functions''  when  he  writes:  "One  of  the  inflexible  rules  which, 
therefore,  must  underlie  the  investigation  of  any  given  ocular 
function  is  'that  such  investigations  must  be  conducted  under 
conditions  of  activity  or  quiescence  which  conform  to  the  phil- 
osophy of  the  particular  phase  of  its  activity  under  considera- 
tion'. "  We  have  previously  discussed  near-point  determina- 
tions by  the  use  of  reading  test-types  and  have  pointed  out 
valid  objections  to  placing  the  dependence  in  and  upon  them 
such  as  is  desirable  in  all  ocular  investigations.  And  here  again 
one  of  the  most  valid  objections  is  that  normally  accommodative 
demands  are  not  made  upon  the  visual  machine  at  three  or  four 
inches  from  the  eyes;  all  emmetropes,  or  those  who  are  prac- 
tically so  by  nature  or  by  optical  assistance,  read  and  do  all 
so-called  "near  work"  at  about  twelve  to  fifteen  inches.  The 
requirements  for  comfortable  binocular  vision  imposed  by  the 
function  of  convergence  have  doubtless  been  the  determining 
factor  in  establishing  the  commonly  accepted  normal  reading 
point  and  not  the  function  of  accommodation,    for  it  has  been 


Course  No.  14 
Page  33 

conclusively  shown  (see  the  research  of  Landolt  and  others) 
that  at  least  one  half  to  possibly  two-thirds  of  the  total  conver- 
gence amplitude  must  be  held  in  reserve  if  comfortable  binocular 
vision  is  to  ensue.  The  average  pair  of  eyes  (64  mms.  pupillarv 
width)  exert  approximately  18A  of  convergence  when  fixing 
at  the  13  inch  point  and  should  have  in  reserve  at  least  an  equal 
quantity,  /.  e.,  1 5A  to  20A.  Such  positive  convergence  amplitude, 
if  normal  development  in  youth  accrues  and  if  undue  demands 
upon  it  by  virtue  of  an  inharmonious  correlation  of  accommo- 
dation and  convergence  are  rectified  or  sufficiently  assisted, 
remains  practically  constant  throughout  the  usual  span  of  a 
lifetime.  Accommodation,  however,  decreases  with  increasing 
years,  not  presumably  because  of  weakened  innervation  or 
insufficient  motor  centers,  but  because  of  lenticular  changes, 
such  as  loss  of  elasticity,  which  make  curvature  changes  under 
the  action  of  the  ciliary  impossible.  Or  possibly  the  Mueller's 
muscle  weakens  and  is  less  responsive  to  innervation  as  increas- 
ing years  creep  on.  Doubtless  both  ciliary  weakness  and 
lenticular  changes  are  responsible  for  the  diminution. 

The  major  portion  of  all  our  near  work  is  most  advanta- 
geously done  at  about  thirteen  inches.  As  a  result,  therefore, 
the  accommodative  demands  are  met  with  respect  to  this  point. 
It  seems,  then,  that  by  far  the  most  logical  subjective  method 
would  be  to  investigate  the  accommodative  resources  at  the 
ordinary  reading  point.  The  method  is  easily  and  readily 
carried  out.  The  test  should  be  made  monocularly  and  in  front 
of  each  eye  as  tested  should  be  placed  the  distance  finding, 
particularly  the  cylindrical  element.  The  spherical  element 
should  be  the  maximum  convex  or  minimum  concave  lens  which, 
either  alone  or  in  combination  with  a  cylinder  as  the  case  may  be, 
aflFords  V  =  20/20  or  as  nearly  the  normal  standard  as  condi- 
tions will  permit.  If  distant  vision  can  be  raised  to  normal 
or  not  less  than  8/10,  the  writer  uses  the  No.  2  Jaeger  type 
(V  =  o.5  D.  S.)  as  the  standard  in  conducting  the  test  under 
description.  Such  test-type  being  held  at  thirteen  inches,  the 
distance  correction  being  worn,  the  ciliary  must  then  exert  3 
diopters  of  accommodative  action  and  produce  3  diopters  of 
lenticular  action,  or  3  diopters  refractive  change,  it  acting 
normally  when  the  eye  reads  fine  print  at  the  distance  specified. 
Minus  spheres, '  commencing  in  general  with  a  —  i  or  —1.5 
diopter  glass  (although  this  should  be  regulated  by  our  knowledge 
of  the  probable  amplitude  of  accommodation  as  judged  from  the 
age  of  the  patient),  are  then  inserted  or  turned  up  in  the  lens 
battery  in  conjunction  with  the  phoro-optometer  until  the 
maximum  minus  lens  has  been  inserted  through  which  No.  2 
Jaeger  is  barely  readable.  By  this  method  of  testing,  the 
operator  is  furnished  data  upon  the  total  accommodative  ampli- 
tude as  available  at  the  reading  point. 

Advantages  and  Disadvantages  of  this  Method.  Possibly  one 
of  the  chief  disadvantages  in  the  use  of  concave  lenses  in  the 


Course   No.  14 
Page  34 

testing  of  the  accommodative  resources  lies  in  the  reduction 
in  the  sizes  of  the  retinal  images  and  hence  of  the  apparent 
size  of  the  type  read.  The  well-known  action  of  concave  lenses 
is  to  minimize  the  size  of  objects  seen  through  them.  Their 
insertion  before  an  eye  demands  that  the  corresponding  accom- 
modative changes  on  the  part  of  the  lens  be  produced  if  the 
object  is  to  be  clearly  seen,  /'.  e.,  the  accommodative  mechanism 
must  adjust  itself  to  the  added  divergency  caused  by  the  wearing 
of  the  concave  lens.  The  simple  formula  which  connects  the 
object  and  image  conjugates  and  the  focal  length  of  a  single 
thin  lens  is 

I        I        I 

fi      U      F 

in  which /i  represents  the  image  distance, /2  the  object  distance, 
and  F  the  focal  length  of  the  lens.  In  the  case  of  a  negative 
or  diverging  lens  the  formula  reads 

I        I  I 

fi      U         F 

If,  then,/i  is  taken  as  the  object  distance,  namely,  at  a  constant 

I 
distance  of  13  inches,  and  —  is  taken  in  turn  as  equivalent  to 
F 

—  iD.,  —2D.  and  so  forth,  a  simple  calculation  will  show  that 
fj  is  respectively  —10  inches,  —8  inches,  —6.66  inches  and  so 
on  in  front  of  the  lens.  This  demands,  therefore,  that  4  D., 
5  D.  and  6  D.  respectively  of  accommodation  be  exerted  to 
see  the  object  under  examination  distinctly  at  the  thirteen 
inch  point.  But  two  factors  enter:  (i)  The  size  of  the  image 
produced  by  the  concave  lens  decreases  in  the  following  ratio: 

Object  size         Object  distance 


Image  size  Image  distance 

To  illustrate:  If  the  object  is  one  centimeter  high,  then 
the  following  brief  table  shows  the  sizes  of  the  images  as  pro- 
duced by  the  lens  having  the  focal  length  specified;  the  position 
of  the  object  is  held  constant  at  thirteen  inches. 

Object  i  cm.  High  at  Thirteem  Inches 


Object 
Position 

Image 
Position 

Lens 
Inserted 

Size  of 

(Inches) 
13 

(Inches) 
13 

(Diopters) 
No  lens 

Image 

I 

13 

10 

-I  D. 

10/13 

13 
13 

8 
6.66 

-2D. 
-3D- 

8/13 
62/3/13 

Course   No.  14 
Page  35 

Such  effects  as  these  would  be  produced  by  the  concave  lenses 
alone.  (2)  But  these  images  are  affected  in  their  sizes  in 
that  they  are  increased  by  the  action  of  the  accommodative 
mechanism  upon  the  crystalline  lens.  The  crystalline  lens  being 
thickened  at  the  center  under  the  ciliary  action  and  the  chief 
seat  of  this  action  lying  in  the  anterior  crystalline  surface,  the 
eye  will  have  its  nodal  points  changed  and  its  equivalent  single 
nodal  point  removed  further  from  the  retina,  with  the  result 
that  the  visual  angle  will  be  increased  as  compared  with  that 
which  exists  when  concave  lenses  are  inserted  before  the  eye  and 
no  accommodative  action  occurs.  This  subject  is  rather  intri- 
cate and  has  been  treated  in  part  by  Bordier.  An  account  of 
his  calculations  is  to  be  found  in  the  Encyclopedic  francaise 
d'Ophtalmologie,  Volume  III.  The  net  result  is,  therefore,  a 
minimizing  of  the  retinal  images  and  hence  of  the  apparent 
size  of  the  test-objects:  it  should  be  expected  then  that  the 
determinations  upon  the  amplitude  of  accommodation  as 
made  by  concave  lenses  would  be  lesser  in  amount  than  by 
near-point  measurements.  In  the  state  of  accommodation, 
however,  which  is  a  temporary  myopia  ot  curvature,  the  two 
nodal  points  will  be  displaced  toward  the  cornea.  For  the 
accommodation  necessary  at  a  quarter  ot  a  meter,  it  can  be 
shown  that  the  relative  increase  of  the  retinal  image  is  approx- 
imately one-fifth  of  the  size  which  it  possesses  when  in  a  state  ot 
repose.  It  is  thus  seen  how  the  shifting  of  the  nodal  point  away 
from  the  retina  compensates  in  a  considerable  measure  for  the 
reduced  sizes  of  images  due  to  concave  glasses  when  used  in  the 
manner  under  discussion. 

The  reader  can  refresh  his  memory  upon  the  conditions 
which  exist  when  a  test-object,  such  as  a  line  of  No.  2  Jaeger 
type,  is  read  and  the  amplitude  of  accommodation  determined 
by  finding  the  punctum  proximum,  by  reference  to  the  paragraphs 
in  which  this  method  was  discussed.  Let  it  be  briefly  stated 
here,  however,  that  the  effects  are  just  the  reverse  or  opposite 
of  those  obtained  by  the  concave  lens  method,  since  retinal 
images  will  be  increased  in  size  due  to:  (a),  approach  of  constant- 
sized  test-object  toward  the  eye;  (b),  contraction  of  pupil, 
and  (c),  narrowing  of  palpebral  fissure  in  certain  cases.  We 
should,  therefore,  conclude  that  the  near  point  methods  will 
all  lead  to  higher  values  of  the  accommodative  amplitude;  while 
concave  lenses,  whether  used  in  testing  the  accommodation  at 
twenty  feet  or  at  the  reading  point,  as  now  under  discussion, 
will  lead  to  much  lower  values.  The  writer  believes,  then, 
that  the  results  of  the  two  methods  should  be  in  general  averaged 
as  giving  the  correct  measure  of  the  available  accommodation 
in  cases  of  normal  visual  acuity  and  upon  the  exhibition  of  a 
quantum  of  accommodative  action  which  is  regular  and  easy 
throughout  its  whole  range  and  which  is  comparable  to  that 
which  should  normally  be  expected  of  the  patient  at  the  age 
given. 


Course   No.  14 
Page  36 

Some  Simple  Illustrations  of  the  Principles  Involved  in 
This  Method.  A  few  simple  illustrations  of  clinical  or  office 
practice  involving  this  method  may  not  be  inappropriate.  Let 
us  assume  a  distance  correction  of  +1  D.  S. 0+0.50  cyl.  ax.  90 
affording  practically  normal  vision.  The  practitioner,  then, 
armed  with  the  information  that  the  visual  acuity  is  normal 
for  distant  seeing,  hands  the  patient  the  reading  test-chart, 
occludes  the  eye  not  under  test  and  directs  the  patient  to  read 
the  No.  1  Jaeger  type  when  held  at  thirteen  inches,  or,  better 
still,  inserts  the  small  reading  card  furnished  with  the  phorometer 
in  the  slide  provided  with  such  an  instrument  and  sets  it  at  the 
thirteen  or  fourteen  inch  point.  The  test  is  then  carried  on, 
using  minus  spheres,  until  the  maximum  concave  lens  is  found 
through  which  the  No.  2  type  is  just  readable  or  some  of  the 
commoner  words  can  be  made  out.  If  the  practitioner  has 
at  his  command  a  phoro-optometer  the  lenses  may  be  readily 
changed  and  by  as  small  steps  as  seem  desirable.  It  need 
hardly  be  said  that  memory  or  academic  vision  must  be  elim- 
inated from  such  a  test;  hence  as  the  patient  reads  a  portion  of 
a  line  it  is  well  to  "turn  in"  minus  lenses  as  rapidly  as  the  re- 
sponse of  the  person  under  observation  permits  until  the  read- 
ing becomes  sufficiently  difficult  as  to  involve  rather  slow  prog- 
ress in  its  accomplishment.  The  accommodation,  if  strong  and 
active,  should  respond  readily  to  the  demands  made  upon  it 
up  to  within  possibly  three-quarters  of  its  total  capacity.  To 
return,  then,  to  our  illustrative  case,  we  turn  up  —2,  —3,  —3.5, 
—  4  diopters  and  so  on,  giving  the  ciliary  time  to  respond  in  each 
case,  until  finally,  let  us  say,  with  a  —5  D.  S.  reading  is  difficult 
and  with  a  —6  D.  S.  the  reading  of  much  larger  type  is  impossible. 
We  therefore  conclude  that  the  total  accommodation  available 
at  the  thirteen  inch  reading  point  as  evidenced  by  this  modus 
operandi  is,  as  a  maximum,  9  diopters.  This  9  diopters  is  the 
sum  of  the  3  diopters  exerted  by  the  accommodative  mechan- 
ism in  order  to  read  at  thirteen  inches  and  the  6  diopters  of 
additional  accommodation  as  elicited  by  the  concave  lenses 
inserted. 

If,  again,  with  —2D.  S.,  V  =  20/20,  these  tests  upon  the 
accommodative  resources  are  instituted,  the  patient  wearing 
the  distance  correction,  and  it  is  found  that  a  —3  D.  S.  meas- 
ures the  maximum  reserve  at  thirteen  inches,  it  may  then  be 
concluded  that,  under  the  conditions  through  and  by  which  the 
tests  are  made,  some  6  diopters  of  accommodation  are  available 
and  can  be  effectually  put  into  operation  at  the  reading  point. 

Reasons  for  the  Insertion  of  Distance  Binocular  Findings 

When  Investigating  the  Accommodative  Resources 

at  the  Reading  Point 

There  are  certain  very  valid  and  important  reasons  for  the 
insertion  of  the  findings  affording  best  acuity  conditions  at  dis- 
tance before  the  eye  under  test.     By  the  expression  "best  acuity 


Course  No.  14 
Page  37 

conditions  at  distance"  we  very  naturally  refer  to  the  binocular 
findings  which  have  ministered  to  the  refractive  conditions  to 
the  full  amount  of  hyperopia  possible  and  given  us  the  minimum 
findings  in  myopia. 

(i)  Investigations  upon  the  accommodative  resources 
normally  follow  (at  least  such  is  my  practice)  after  the  obtain- 
ment  of  static  and  dynamic  retinoscopic  findings,  subjective 
testings  and  the  investigations  upon  the  muscular  equipoise 
under  static  and  dynamic  conditions.  Incidentally  it  may  be 
stated  that  in  the  writer's  investigations  upon  the  muscular 
condition  as  exhibited  at  distant  and  near-points  the  patient 
is  provided  with  what,  in  the  writer's  judgment,  in  so  far  as 
data  at  hand  can  direct  him,  will  constitute  the  binocular  cor- 
rections. Such  binocular  corrections  consist  of  the  maximum 
convex  and  minimum  concave  lenses  affording  practically  normal 
acuity  when  such  is. obtainable,  although  we  are  quite  prone, 
both  from  theoretical  grounds  and  from  experience,  to  slightly 
fog  binocularly  in  young  hyperopes  and  to  leave  the  binocular 
myopic  corrections  in  cases  of  reasonable  quantities  thereof 
such  as  to  afford  not  much  better  than  8/10  vision.  In  the 
determination,  therefore,  of  the  reserve  accommodation  at 
thirteen  inches  the  eye  under  test  is  furnished  with  practically 
that  correction  which,  unless  other  tests  have  indicated  or  the 
one  under  discussion  should  indicate  to  the  contrary  as  not 
adequately  meeting  all  the  economic  binocular  demands,  it  will 
ultimately  receive.  Hence,  the  tests  upon  the  total  accommoda- 
tive reserve  are  made  under  conditions  imposed  upon  them  by  the 
optical  corrections  and  assistance  which  the  static  refractive 
errors  have  demanded  and  which  they  may  perchance  ultimately 
receive.  We  have,  in  other  words,  primarily  determined  through 
our  static  tests  at  twenty  feet  the^efractive  assistance  which  is 
needed  in  the  interests  of  the  establishment  of  best  or  most 
comfortable  visual  acuity  conditions  or  the  restraint  of  abnormal 
ciliary  action  and  so  forth  and  are  desirous  of  knowing  whether 
or  not  such  a  correction  will  fit  in  with  the  economic  and  com- 
fortable operation  of  accommodation  and  convergence  at  near 
points  and  whether  or  not  the  new  demands  or  readjustments 
imposed  upon  the  accommodation  are  such  as  to  afford  an 
harmonious  correlation  of  functions  without  imposing  condi- 
tions upon  any  one  function  which  may  cause  our  final  solution 
as  to  the  needs  of  a  pair  of  eyes  to  be  inadequate  or  unbalanced 
from  the  functional  standpoint. 

(2)  The  wearing  of  the  distance  correction  will  furnish 
the  eye  with  such  optical  assistance  as  to  insure  the  practitioner 
that  its  manifest  punctum  remotum  will  be  situated  practically  at 
infinity  and  that,  therefore,  its  accommodative  mechanism  has 
been  so  aided  as  to  permit  of  its  meeting  most  advantageously 
the  normal  demands  made  upon  it  as  the  fixation  point  is  moved 
from   twenty   feet   to   thirteen   inches.     In   other  words,   when 


Course  No.  14 
Page  38 

furnished  with  its  full  distance  correction  its  range  of  accommo- 
dation is  not  afi^"ected  as  would  be  the  case  if  its  myopic,  hyperopic 
or  more  particularly  its  astigmatic  errors  had  not  been,  in  large 
measure  at  least,  corrected.  This  point  appears  to  the  writer 
to  be  an  important  one  in  the  modus  operandi  of  this  particular 
method  of  testing  accommodative  quanta;  eyes  when  tested 
either  singly  or  in  co-ordination  should  be  as  nearly  emmetropic 
as  our  various  tests  enable  us  to  render  them. 

(3)  The  practitioner  is  relieved  from  the  necessity  of 
making  the  very  simple  but  apparently,  to  many,  rather  confusing 
arithmetical  computation  as  to  the  total  accommodation  avail- 
able; the  total  available  accommodation  is,  when  the  distance 
findings  are  worn,  represented  as  the  lenticular  equivalent  of 
the  maximum  concave  lens  inserted  plus  the  three  diopters  of 
accommodation  demanded  by  fixation  and  reading  at  thirteen 
inches.  If,  for  example,  an  eye  genuinely  myopic  5  diopters 
were  under  test  with  fine  print  at  thirteen  inches,  it  would  be 
impossible  for  such  an  eye  to  read,  since  the  far-point  thereof, 
when  uncorrected,  would  be  at  eight  inches;  such  a  case  would 
therefore  demand  that  at  least  enough  concave  lens  be  inserted 
to  carry  the  far-point  beyond  the  point  of  the  test  in  hand. 
And  again,  to  illustrate  the  arithmetical  calculation  just  men- 
tioned, assume  that  a  hyperope  of  2  diopters  uncorrected,  is 
able  to  read  fine  print  at  thirteen  inches  through  —3  D.  S.; 
the  total  accommodation  is,  then,  8  diopters,  of  which,  however, 
without  correction,  only  3  diopters  is  in  reserve,  since  5  diopters 
are  demanded  to  supply  the  requisite  2  diopters  accommodation 
to  overcome  the  hyperopia  and  furnish  the  necessary  3  diopters 
normally  demanded  at  thirteen  inches.  A  myope,  on  the  other 
hand,  of  2  diopters,  reading  at  thirteen  inches  through  the 
maximum  concave  lens  possible,  let  us  say  —3  D.  S.,  has  a  total 
accommodative  amplitude  of  4  diopters  only  and  a  reserve  of 
3  diopters,  since  an  uncorrected  myope  of  2  diopters  exerts  but 
I  diopter  of  accommodation  in  reading  at  thirteen  inches.  It 
is  very  questionable,  however,  as  to  whether  these  figures 
representing  the  accommodative  demands  in  the  interest  of 
overcoming  the  refractive  errors  are  correct,  since  it  can  be 
demonstrated  from  calculation  upon  the  effectivity  of  lenses 
situated  at  the  usual  distances  from  the  eye  that  the  accommo- 
dation exerted  in  corrected  hyperopia  is  greater  and  in  corrected 
myopia  is  less  than  would  appear  from  ordinary  considerations 
involving  the  optical  equivalence  of  linear  distances.  For 
calculations  show  that  a  hyperope  of  5  diopters  when  corrected 
must  exert  some  3.45  diopters  while  reading  at  2>2>  cms.  and  a 
corrected  myope  of  5  diopters  must  accommodate  only  2.38 
diopters  at  the  same  point.  All  other  things  being  equal,  then, 
a  myope  and  hyperope  of  equal  quantities  of  error,  of  the  same 
age,  pupillary  conditions  and  so  forth,  should  not  presumably 
show  equal  quantities  of  accommodative  resources.  That  is 
to  say,  the  myope  should  exhibit  greater  amplitude  of  accommo- 


Course   No.  14 
Page  39 

dation  and  greater  reserve.  Of  course  this  result  or  this  condi- 
tion of  affairs  may  easily  be  vitiated  due  to  the  fact  that  by 
non-usage  the  accommodation  may  have  become  inefficient  in 
myopia  or,  again,  non-available  through  spasm  of  the  accom- 
modation, ciliary  hypertrophy  and  so  on  in  hyperopia. 

(4)  The  practitioner  is  afforded,  when  the  patient  is 
wearing  the  binocular  distance  findings,  a  ready  and  safe  basis 
for  those  modifications  which  he  may  desire  to  incorporate  in 
the  prescription  that  he  ultimately  gives  the  patient  by  reason 
of  the  tests  upon  the  accommodative  amplitude  and  reserve 
and  upon  the  muscular  poise  at  the  reading  distance.  We  will 
illustrate  the  purport  of  this  remark  by  the  findings  in  a  case 
which  has  just  left  our  hands  and  which  caused  an  interruption 
in  the  penning  of  these  sentences.  A  young  man,  aged  23  years, 
came  to  us  wearing  O.  U.  —.25  D.  S.,  as  we  discovered  after 
finishing  our  own  tests.  These  glasses  he  said  had  been  given 
him  for  distant  use  only  and  that  he  was  admonished  to  remove 
them  while  reading.  He  complained  of  that  tired  feeling, 
ocular  fatigue,  sleepiness  creeping  upon  him  while  reading, 
and  said  that,  contrary  to  instructions,  he  had,  in  his  desire 
to  see  what  he  could  do  to  improve  matters,  worn  his  glasses 
while  reading  and  that  they  seemed  to  benefit  him  for  a  short 
time  but  were  soon  of  no  service.  Static  retinoscopy  disclosed 
an  erratic  or  spasmodic  condition,  O.  U.+0.50  D.  S.  being 
apparently  the  approximate  findings.  It  was  found  that 
binocularly  V  =  2o  20  practically  with  O.  U.  +  .75  D.  S.,  although 
slightly  blurred.  The  muscular  poise,  both  at  distant  and 
near-points,  these  lenses  being  worn,  disclosed  no  conditions  of 
imbalance.  The  monocular  near-point  proved  to  be  at  about 
six  inches,  equivalent  therefore  to  7  diopters  roughly,  and  the 
tests  with  minus  lenses  disclosed  the  fact  that  his  total  available 
accommodation,  after  much  coercion,  did  not  exceed  6.5  diopters, 
the  eye  being  assisted  by  the  +-75  t)-  S.  Dynamic  skiametry 
evidenced  the  need  of  lenticular  assistance  at  the  reading  point 
to  the  extent  of  O.  U.  + 1  -5  D.  S.  In  the  light  of  all  the  evidence 
furnished  we  felt  justified  in  prescribing  O.  U.+  i  D.  S.  to  be 
worn  while  reading  and  to  be  gradually  "worked  into"  for 
distance  as  well,  when  they  would  presumably  adequately  meet 
the  ocular  demands  and  afford  ocular  comfort.  Experience  has 
demonstrated  that  in  nine-tenths  of  such  cases,  with  proper 
instructions  to  the  patient,  such  refractive  treatment  will  solve 
such  ocular  problems  as  this.  And,  by  the  bye,  \ve  always 
take  occasion  to  point  out  to  the  patient  the  trend  oi  probable 
experiences  to  be  encountered  in  the  readjustment  ot  the  ocular 
functions  to  normal  conditions  and  send  the  patient  away  with 
the  statement  that  we  shall  expect  another  visit  for  inspection 
not  earlier  than  a  week  or  ten  days.  He  who  fails  to  see  to  it 
that  his  patient  returns  to  him  in  due  time  is  not  wise  and  he,  in 
turn,  who  has  his  patient  at  his  heels  the  morning  after  is  less 
wise  and  has  failed  to  exercise  that  psychological  control  which 


Course   No.  14 
Page  40 

is  so  essential  in  all  professional  practice.  But  enough  of  this! 
The  patient  asked  us  as  to  whether  or  not  he  could  make  any  use 
of  his  old  lenses  and  we  informed  him  that  he  might  use  them 
with  profit  for  exercise  in  the  rhythmic  manner  described  by 
Savage.  If  you  have  not  thoughtfully  perused  these  methods 
of  rhythmic  exercise  both  for  the  extrinsic  and  intrinsic  muscles, 
take  occasion  to  look  into  Savage's  Ophthalmic  Myology. 

It  is,  of  course,  always  to  be  borne  in  mind  that  accommo- 
dative conditions  will,  in  general,  improve  under  the  proper 
refractive  treatment.  The  constant  use  of  corrective  lenses 
has  the  effect  of  maintaining  and  often  of  restoring  good  accom- 
modative action  if  it  has  become  depleted  owing  to  non-use. 
Likewise,  excessive  accommodation  may  have  been  exerted 
in  near  work  in  cases  of  uncorrected  astigma;  the  proper  cylin- 
drical corrections  will  relieve  this  sectional  ciliary  action  and  in 
time  produce  normal  accommodative  conditions.  And  in  hyper- 
opia we  may  expect  normal  innervation  to  be  accompanied  in 
general  by  normal  responses  in  lenticular  changes  when  read- 
justed ocular  conditions  obtain.  It  is  just  as  reasonable  to 
expect  such  physiologic  reactions,  especially  in  the  young,  in 
ocular  functions  as  would  be  looked  for  in  the  ultimate  normal 
functionings  of  the  muscles  in  an  arm  which,  either  from  non- 
use  or  from  excessive  use,  have  become  abnormal  in  their  responses. 
The  insufficiency  does  not,  therefore,  immediately  disappear 
on  application  of  the  correcting  lenses  because  the  defect  has 
become  more  or  less  chronic  and  hence  does  not  at  once  respond 
to  the  removal  of  the  cause.  We  should  look  for  results  in 
accommodative  changes  similar  to  those  experienced  in  muscular 
imbalances  in  which  usually  we  do  not  find  immediately  any 
marked  alteration  in  the  imbalance  when  correcting  lenses 
are  applied. 

The  writer  believes  from  his  experiences  with  dynamic 
skiametry  that  this  system  of  ocular  refraction  does,  in  general, 
disclose  that  refraction  assistance  which  may  be  at  the  time  of 
examination  demanded  by  the  accommodation  at  near  points, 
due  regard  in  this  respect  being  given  to  the  demands  which 
may  be  apparently  indicated  as  being  made  by  the  accommoda- 
tive function,  but  which  may  in  reality  be  demanded  in  the 
interests  of  the  proper  correlation  of  accommodation  and  fixa- 
tion at  the  point  of  observation.  We  are,  therefore,  as  a  general 
rule,  inclined  to  take  the  dynamic  findings  as  a  measure  of  the 
maximum  demands  made  by  a  deranged  ocular  system  at  the 
reading  point  and,  with  these  and  other  tests  as  the  basis  upon 
which  to  form  our  judgment,  give  such  corrections  as  we  believe 
will  adequately  aid  the  ocular  functions  to  re-assume  normal 
conditions,  but  not  such  complete  corrections  as  to  wholly 
relieve  the  various  functions  involved  from  any  necessity  of 
action  in  the  re-establishment  of  comfortable  and  economic 
conditions. 


Course  No.  14 
Page  41 

(5)  The  thirteen  inch  or  thirty-three  centimeter  point 
should  be  ordinarily  chosen  as  the  point  at  which  the  accommo- 
dative resources  are  to  be  investigated  rather  than  a  nearer  or 
more  remote  point,  for  the  reason  that  nature  has  ordained  the 
establishment  of  a  comfortable  convergence  and  a  normal 
distance  of  distinct  vision  at  about  a  foot  from  the  eyes. 

Let  us,  in  passing,  compare  some  of  the  results  obtained  upon 
the  amplitudes  and  ranges  of  accommodation.  One  of  the  most 
interesting  discussions  upon  this  subject  is  by  Alexander  Duane, 
in  an  article  entitled:  "The  Anomalies  of  Accommodation  Clinical- 
ly Considered,"  read  before  the  American  Ophthalmological 
Society  in  July,  191 5  (see  The  Keystone  Magazine  of  Optometry^ 
Volume  10,  page  349,  1916).  Near-points  were  determined  by 
measurement  from  the  anterior  focus  of  the  eye,  /'.  ^.,  from  a 
point  13  mms.  in  front  of  the  cornea.  He  says:  "The  patient 
whose  accommodation  we  are  testing  is  placed  with  his  back 
to  the  light  (good,  diffuse  daylight  should  be  used  when  possible), 
and  is  directed  to  look  sharply  at  the  test-object  (a  fine  black 
line  bisecting  a  white  parallelogram  which  is  mounted  on  a  disc 
of  black  velvet).  The  eye  not  under  examination  being  covered, 
the  test-object  is  brought  toward  the  patient  along  a  Prince's 
rule  until  the  fine  line  blurs  and  then  is  carried  back  and  forth 
several  times,  until  we  ascertain  the  nearest  point  at  which  the 
line  can  be  seen  with  perfect  distinctness.  .  .  .  Repeated 
tests  should  be  taken  and  care  must  be  exercised  that  the  results 
are  not  vitiated  by  the  patient's  inattention  or  lack  of  com- 
prehension of  what  is  expected  of  him."  The  average  results 
only  for  each  age  mentioned  are  included  in  the  subjoined 
table. 

The  table  given  by  Jackson  is  generally  accepted  as  being 
as  nearly  correct  as  any.  Of  this  table  Savage  says:  "The 
error,  if  any,  is  in  the  showing  of  too  much  ciliary  power  after 
the  age  of  thirty  years.  This  table  shows  the  relative  or  asso- 
ciated accommodation  and  is  much  greater  than  would  be 
shown  if  accommodation,  unassociated  with  convergence,  were 
tested  with  concave  lenses." 

We  give  these  tables  side  by  side  and  venture  to  add  our 
own  values  from  several  hundred  cases  (ranging  mostly,  how- 
ever, from  fifteen  to  thirty-five  years  of  age)  as  found  by  the 
concave-at-near  tests. 


Course  No.  14 
Page  42 


Amplitudes  of  Accommodation 


Jackson 

(Concave  Sheard 

lenses.  (Monocular 

Accommodation  Test  Object 


associated 

at  13  in.) 

Bonders 

Duane 

with 

Concave 

^ge 

(Near-point)  (Near-poin 

t)  Convergence) 

Lenses. 

10 

14 

n-s^ 

14 

15 

12 

12.6 

12 

II. 0 

20 

10 

II. 5 

10 

9.0 

25 

8.5 

10.5 

9 

7.5 

30 

7 

0 

8.9 

8 

(^.^ 

Z<> 

5 

7-3 

7 

5-0 

40 

4 

5-9 

S-S 

3-75 

45 

3 

3-7 

4 

.... 

50 

1 

2.0 

2.5 

.... 

^S 

I 

75 

1-3 

1.25 

60 

I 

00 

I.O 

0-5 



With  reference  to  the  values  which  the  writer  has  tabulated 
as  determined  by  him  to  be  about  average  values  for  the  ages 
specified  by  the  concave  lens  method  with  observation  at  the 
ordinary  reading  point,  the  writer  has  to  say  that  he  has  never 
seen  in  print  any  table  giving  such  determinations.  It  will  be 
noted  that  they  run  in  general  from  1.5  to  2  diopters  below 
the  values  given  in  the  tables  by  Jackson  and  Duane,  and  are 
more  nearly  in  agreement  (although  considerably  lower)  with 
those  given  by  Bonders.  In  the  obtainment  of  these  data  cases 
only  were  recorded  in  which  the  visual  acuity  could  be  brought 
to  normal  or  20/20  at  distance,  the  maximum  convex  and 
minimum  concave  lens  power,  together  with  the  astigmatic 
corrections,  being  worn  throughout  the  tests.  It  is  of  interest 
to  note  in  passing  that  Thorington  lays  down,  and  very  properly 
so,  as  one  of  the  criteria  to  be  met  in  determining  visual  acuities 
that  the  astigmia  be  first  corrected  by  establishing  equality  of 
lines  in  the  ordinary  astigmatic  chart.  We  ordinarily  use  No.  2 
Jaeger  type  (V  =  o.5  B.  S.)  as  the  standard  test-type  in  the 
determination  of  the  accommodative  resources  at  the  reading 
point  by  means  of  concave  lenses,  and  the  maximum  lens  added 
until  reading  is  impossible  even  under  the  added  impetus  and 
goading  of  the  examiner.  W^e  have  already  remarked  that  in 
general  we  have  found  the  amplitudes  of  accommodation  for 
myopes  of  a  given  age  greater  than  those  of  hyperopes  (both 
being  brought  up  by  means  of  lenticular  assistance  to  normal 
acuity  at  twenty  feet)  for  the  corresponding  period  of  life,  all 
other  factors  being  as  nearly  identical  as  possible.  This  state- 
ment probably  holds  good  for  those  possessed  of  small  errors 
or  in  cases  in   which  the  refractive  errors  have  been  properly 


Course   No.  14 
Page  43 

cared  for  in  the  past.  It  cannot  be  in  general  expected  that 
maximum  values  of  accommodative  amplitudes  will  he  obtained 
in  high  myopic  or  hyperopic  errors  upon  their  initial  correction, 
tor  in  one  case  there  has  been  a  subnormal  demand  upon  accom- 
modation and  in  the  other  case  there  has  been  an  abnormal 
demand,  hence  there  may  be  weakness  in  one  case  due  to  non- 
use  and  in  the  other  condition  weakness  due  to  overstrain  of 
the  ciliary  muscle,  together  with  abnormal  nutritive  processes 
developed  in  the  ciliary  body  and  the  lens.  It  is  probable, 
however,  in  those  refractive  conditions  which  are  low  in  value 
or  which,  it  high,  have  been  corrected  over  a  period  of  years 
that  a  greater  amplitude  of  accommodation  will  as  a  general 
proposition  be  developed  in  myopia  as  compared  with  hyperopia. 

A  Case  Illustrative  of  Pseudo  Near-points  arid  the  Unre- 
liability of  Conclusions.  In  some  preceding  paragraphs  atten- 
tion has  been  directed  to  the  possibility  that  the  use  of  the  near- 
point  determinations,  such  as  by  the  reading  of  fine  print,  for 
the  determination  of  the  amplitude  of  accommodation  and  its 
range  may  lead  to  spurious  results.  Briefly,  in  resume,  the 
reasons  are:  {a)  increase  of  size  of  retinal  image  with  approach 
of  the  constant  sized  type  to  the  eye,  {b)  pupiFlary  contraction, 
thus  cutting  down  the  sizes  of  the  diffusion  or  confusion  cir- 
cles and  {c)  the  narrowing  of  the  palpebral  fissure,  particularly 
in  cases  of  astigmia. 

We  shall  in  the  succeeding  paragraphs  present  a  case  which 
is  amongst  the  most  interesting  and  probably  most  difficult  in 
ocular  refraction.  Such  cases  are  difficult  for  the  reason  that 
they  demand  the  best  judgment  on  the  part  of  the  practitioner 
and  likewise  presume  that  he  is  sufficiently  versed  in  the  general 
systemic  and  symtomatic  conditions  and  after-effects  or  accom- 
paniments of  certain  diseases  such  as  anemia,  diphtheria,  measles, 
scarlet  fever,  neurasthenia,  hysteria  and  so  forth,  as  to  be  able 
to  intelligently  recommend  medical  attention  or  co-operation 
in  the  case  or  withhold  the  same  when  conditions  warrant. 
While  these  cases  admirably  illustrate  pseudo  near-points  and 
the  invalidity  of  data  thereby  obtained,  and  while  they  further 
emphasize  the  necessity  of  examinations  upon  the  accommoda- 
tion and  correlated  functions,  they  likewise  illustrate  conditions 
of  subnormal,  weakened,  pre-presbyopic  or  depleted  accommo- 
dation. In  general,  let  the  writer  say  in  passing,  in  cases  of 
doubt,  where  the  history,  appearance  of  the  patient,  symptoms 
of  which  complaint  is  made  and  all  the  ocular  tests  indicate  a 
possible  paresis  of  the  accommodation,  whether  temporary  or 
permanent,  or  toxemia,  medical  examination  should  be  recom- 
mended and  insisted  upon.  We  have  no  patience  with  the 
non-medical  practitioner  who  fears  to  refer  a  case  in  the  interests 
of  the  patient's  welfare  to  his  or  her  family  physician  or  other 
desired  medical  specialist  lest  the  case  should  fail  to  be  referred 
back  for  refractive  assistance,  and,  in  turn,  let  me  waste  paper 


Course   Xo.  14 
Page  44 

and  ink  enough  to  say  that  we  think  as  little  oi  the  medical 
practitioner  who  fails  to  deal  fairly  with  his  associate  even 
though  he   may  not  agree  with  him. 

We  have  a  clipping  laid  away  in  our  filing  cases,  evidently 
taken  from  an  optical  magazine,  which  we  shall  quote  with  the 
expression  of  regret  that  we  cannot  give  the  writer's  name,  since 
the  clipping  is  but  an  excerpt  from  the  article  in  which  it  appeared. 
However,  possibly  it  is  just  as  well,  since  we  radically  disagree 
with  most  of  the  writer's  statements.  The  clipping  referred  to 
reads:  "There  are  some  children  who  habitually  read  and  write 
at  too  short  a  distance.  Their  parents  and  teachers  are  contin- 
ually telling  them  not  to  get  so  close  to  the  slate  or  paper,  but 
they  persist  in  the  bad  habits,  which  undoubtedly  often  lead 
to  myopia  or  strabismus.  I  believe  these  children  can  only  use 
their  eyes  in  comfort  at  such  a  close  range.  The  trouble  is  a  spasvi 
of  accommodation y  that  comes  on  when  they  do  close  work. 
They  may  try  to  see  well  at  thirteen  inches  but  the  eyes  -i^ant  to 
focus  at  ten  inches.  So  they  move  up  close  and  keep  on  coming 
closer  until  the  effort  put  in  the  ciliary  becomes  sufficient  in  amount 
so  that  coyivergence  and  accomjnodation  balance.^  ivhen  they  feel 
cotnfortable.  We  might  give  such  children  concave  lenses  to  read 
with,  though  in  so  doing  we  would  make  ourselves  liable  to 
charges  of  optometric  incompetency,  or  what  would  be  better, 
a  pair  of  prisms  might  be  worn  to  relieve  the  convergence  and, 
therefore,  reduce  the  ciliary  innervation.  As  a  matter  of  fact, 
when  parents  become  alarmed  by  this  habit  in  children  and 
have  them  examined  for  glasses,  the  refractionist  thinks  that 
he  has  done  the  right  thing  when  he  has  corrected  the  refractive 
error  for  distance  no  matter  how  small  it  may  be.  There  is 
only  one  certain  proof  of  spasm  of  accommodation  due  to  hyper- 
trophy of  the  ciliary  and  that  is  the  development  of  latent  error. 
All  other  methods  are  guesses  that  are  just  as  apt  to  be  wrong 
as  right.  When  it  comes  to  the  other  variety  of  spasm  of  accom- 
modation, that  due  to  excessive  innervation  of  the  ciliary  muscle^ 
the  only  proof  of  its  relief  is  the  comfort  produced  either  by 
wearing  minus  lenses  or  prisms  base  out!' 

We  have  quoted  this  paragraph  at  length  and  italicized 
some  of  the  portions  with  which  we  disagree.  The  statement 
"that  such  children  use  their  eyes  in  comfort  at  such  close 
range"  is  incorrect;  there  is  no  particular  comfort  involved  in 
it  but  there  is  often  vision  which  is  apparently  impossible  at 
greater  distance  because  of  the  increase  ot  sizes  of  retinal  images 
and  other  physiological  factors  to  which  reference  has  been 
made  several  times  in  these  pages.  By  carefully  watching  such 
children  one  is  often  led  to  the  conclusion  that  the  major  portion 
of  this  very  close  reading  is  done  monocularly,  since  such  children 
move  their  heads,  almost  from  letter  to  letter,  instead  of  their 
eyes  and  invariably  keep  throwing  up  a  hand  and  rubbing  one 
eye,  usually  the  left,  or  more  specifically,  the  eye  with  poorer 


Course  No.  14 
Page  45 

vision.  Squint  or  strabismus,  in  the  proper  significance  of  the 
term,  does  not  in  general  develop  after  the  age  of  six  or  seven 
years  when  the  fusion  faculty  has,  according  to  Worth,  been 
fully  developed.  Certain  it  is,  however,  that  troublesome  and 
equally  disturbing  heterophorias  may  develop.  Furthermore, 
it  is  stated  that  "they  may  try  to  see  well  at  thirteen  inches  but 
the  eyes  want  to  focus  at  ten  inches."  If  such  were  true  then 
such  eyes  would,  in  attempting  to  read  at  thirteen  inches, 
endeavor  to  focus  or  would  focus  at  ten  inches,  hence  if  one  eye 
isoccluded  and  the  skiascope  carrying  a  printed  card  is  used  at 
thirteen  inches,  fixation  and  observation  being  one  and  the 
same  point,  while  the  full  distance  correction  is  worn,  such  eyes 
should  exhibit  or  evidence  a  myopic  condition  corrigible  by  minus 
lenses  and  reading  would  be  made  possible  at  such  a  distance. 
The  same  criterion  would  hold  in  the  binocular  use  of  dynamic 
skiametry  unless  a  reasonably  large  heterophoric  condition  at 
near  should  exist.  We  have  to  say  that  we  have  never  seen  a 
case  which  fulfills  the  conditions  which  we  have  specified  above. 
That  by  "moving  up  closer  until  the  effort  put  in  the  ciliary 
becomes  sufficient  in  amount  so  that  convergence  and  accom- 
modation balance,  when  they  feel  comfortable"  is  impossible. 
For  if  the  ciliary  response  is  not  normal^  the  associated  innervation 
to  the  convergence  will  not  be  normal  and  the  burden  ivill  be  throv:n 
upon  the  fusional  convergence  centers  (either  divergent  or  con- 
vergent as  the  case  may  be).  In  fact,  in  very  young  children  in 
which  strabismi  develop  or  bad  muscle  imbalances  are  set  up, 
one  of  the  primary  causes  underlying  the  same  is  the  breaking 
down  of  the  fusional  impulses  under  excessive  load  or  burden. 
Moreover,  in  nearly  all  cases  of  a  similar  nature  to  those  under 
discussion,  dynamic  skiametry  when  practiced  at  thirteen  inches, 
with  either  binocular  or  monocular  (one  eye  excluded)  fixation, 
shows  that  the  accommodative  resources  are  in  need  of  con- 
siderable additional  assistance  at  the  reading  point.  And 
again,  in  mose  cases  of  this  character,  the  accommodati'ce- 
convergence  tests  at  thirteen  inches  show  a  condition  of  esophoria 
indicating  that  the  innervation  as  delivered  through  the  asso- 
ciated accommodative  channels  is  more  than  ample  but  that 
lenticular  changes  do  not  normally  occur;  there  is,  in  part  at 
least,  a  paresis  of  the  ciliary.  The  use,  therefore,  of  minus  lenses 
in  such  cases,  unless  they  be  used  in  rhythmic  exercising  as 
recommended  by  Savage,  would  be  in  general  absolutely  irre- 
concilable with  the  demands  in  such  conditions,  since  it  would 
add  to  the  burdens  of  the  already  overtaxed  or  irresponsive 
accommodative  action  and  would  increase  the  accommodative- 
convergence.  The  pris?ns,  base  in,  to  relieve  the  fusional  con- 
vergence would  be  more  logical  certainly,  since  this  would  leave 
the  convergence  and  actual  accommodative  points  more  nearly 
at  the  same  point  by  virtue  of  the  fact  that  they  would  thus 
relieve  and  thereby  make  available  an  equal  quantity  of  fusional 
convergence.    However,  such  prisms  cannot  reduce  ciliary  inner- 


Course  No.  14 
Page  46 

vation;  the  only  way  to  reduce  ciliary  innervation  is  by  the  use 
ot  convex  lenses.  One  can,  however,  add  to  or  reduce  from  the 
load  upon  the  fusional  convergence  by  the  use  of  prisms.  We 
are  positive  that  the  best  practitioners  of  visual  optics,  opto- 
metry, or  ophthalmology  would  agree  that,  in  cases  such  as  we 
have  commented  upon,  the  maximum  convex  lens  correction 
wearable,  with  a  fair  degree  (8/10)  of  normal  acuity,  should  be 
initially  prescribed  and  the  seat  of  the  subnormal  accommo- 
dation determined.  We  likewise  feel  that  in  many  cases  an 
auxiliary  pair  of  reading  glasses  to  be  worn  when  engaged  at 
close  work  for  any  length  of  time  should  be  prescribed  and  used 
until  further  tests  show  that  they  can  be  discarded.  Ciliary 
spasms  do  not  in  general  reveal  themselves  by  a  reduction  in 
the  hyperopic  distance  error  at  near-points  as  evidenced  by 
dynamic  skiametry;  rather  do  they  appear  to  be  alleviated  and 
in  large  part  reduced  as  convex  lens  power  is  added  under  the 
dynamic  skiametric  procedure.  This  is  to  my  mind  one  of  the 
most  valuable  assets  of  dynamic  skiametry,  whether  we  call 
such  conditions  spasms  of  accommodation,  or  subnormal,  or 
depleted  accommodation.  For  at  the  reading  distance  a  con- 
siderable expenditure  of  energy  is  involved,  and  a  relaxation  of 
the  ciliary  may  be  more  readily  induced  by  the  offering  of 
external  lens  assistance  under  these  conditions  than  at  infinity; 
or,  in  cases  of  subnormal  or  depleted  accommodation  as  properly 
distinguished  from  spasm  of  accommodation,  additional  convex 
power  will  be  accepted  in  the  interest  of  accommodative  effi- 
ciency and  the  proper  correlation  of  accommodative-convergence 
and  accommodation.  The  writer  thinks  there  are  many  reasons 
why  the  ciliary,  becoming  with  time  more  or  less  hypertrophied, 
may  become  abnormal  in  its  functions  and,  therefore,  demand 
excessive  innervation  for  the  accomplishment  of  its  function 
in  the  processes  of  accommodation,  or  yet  again,  because  of  its 
abnormal  condition  and  abnormal  action  upon  the  lens,  inter- 
fere with  the  lenticular  nutritive  processes  and  thereby  produce 
an  abnormal  condition  of  non-elasticity  of  the  lens,  thus  ulti- 
mately demanding  an  abnormal  innervation  to  produce  any 
specified   accommodative  change. 

Before  rehearsing  in  detail  a  case  involving  pseudo  near- 
points  and  restricted  amplitudes  of  accommodation,  we  quote 
several  sections  from  various  portions  of  the  Jmcricay^  Ency- 
clopedia of  Ophthalmology  upon  Spasm  of  Accommodation, 
Accommodative  Weakness,  Anemia  in  Eye  Diseases  and 
Chlorosis. 

Spasms  of  Accommodation.  "If  the  pupil  is  much  con- 
tracted, the  near-point  approaches  the  eye,  and  the  range  of 
accommodation  is  apparently  increased.  Generally,  however, 
the  near-point  is  not  nearer  to  the  eye  that  it  can  be  brought  by 
strong  voluntary  effort  at  accommodation.  The  far-point  in 
such   cases    approaches    the    near-point    more   or   less,    and    the 


Course  No.  14 
Page  47 

range  of  accommodation  is  shortened  and  this  certainly  suggests 
myopia.  Other  causes  of  accommodative  cramp  are  hysteria, 
irritation  of  the  eye  from  injury  and  inflammatory  changes." 

Accommodation,  Weakness  and  Paresis  of.  "As  Hess  points 
out,  the  old  idea  that  a  normal  near-point  indicates  normal 
function  of  the  ciliary  muscles  is  not  noticed  in  accommodation 
until  it  is  greater  than  the  latent  accommodation.  Owing  to 
the  fact  that  the  latter  increases  with  advancing  years,  old  people 
may  be  afflicted  with  a  considerable  paresis  of  the  muscles  and 
still  the  near-point  be  normal.  This  fact  has  been  frequently 
overlooked.  ...  If  we  read  that  a  patient  fifty  or  sixty 
years  of  age  has  a  normal  near-point,  and  from  this  draw  the 
conclusion  that  he  has  a  normal  accommodation,  we  must  see 
at  once  that  such  a  conclusion  is  not  tenable,  since  the  ciliary 
muscle  may  be  completely  paralyzed  regardless  of  the  fact  that 
the  accommodation  is  normal.  It  is  for  this  reason  that  sub- 
jective disturbances  resulting  from  ciliary  paresis  or  weakness 
must  in  young  persons  be  more  pronounced  than,  ceteris  paribus, 
in  older  people.  Moreover,  such  disturbances  are  less  marked 
in  myopes  than  in  emmetropes  and  less  in  the  latter  than  in 
hyperopes.  Common  to  all  these  disturbances  is  this  recession 
of  the  near-point  while  the  far-point  remains  in  its  normal  locality. 
The  most  common  clinical  cause  of  accommodation,  paresis  is 
diphtheria,  which  affects  the  ciliary  muscle  only,  the  iris  mus- 
culature remaining  intact.  The  paresis  usually  occurs  in  from 
two  to  three  weeks  after  the  diphtheric  infection,  and  in  most 
cases  recovery  is  complete  after  three  or  four  weeks.  Among 
other  causes  of  paretic  accommodation  are:  Partial  or  total 
paresis  of  the  third  nerve,  various  cerebrospinal  diseases,  hysteria 
and  a  number  of  intoxications  —  ptomaine  poisoning,^ for 
example." 

Anemia  in  Eye  Diseases.  "These  signs  of  a  general  blood 
change  are  most  commonly  associated  with  insufficiency'  of 
accomfJ2odation  —  inability  to  read,  fatigue  of  and  pains  in  the 
eyes,  etc.  Deposits  in  the  retina  and  choroid  and  even  neuro- 
retinitis  with  hemorrhages  also  exist  now  and  then.  The  specific 
new  formations  in  the  lymph  glands  and  spleen,  particularly 
those  that  mark  the  so-called  leukemia,  furnish  another  example 
of  intoxication,  with  definite  ocular  changes." 

Chlorosis  —  Ocular  Sy?nptoms  of.  "The  photophobia  and 
irritability  often  observed  in  the  eyes  of  chlorotics  are  usually 
traceable  to  conjunctivitis  and  blepharitis  and  these  again  may 
result  from  overta~xing  of  a  weakened  accommodation  which 
often  leads  to  hyperemia  of  both  the  external  and  internal  eye." 

Illustrative  Case  A.  A.  E.  G.  A  colored  boy,  ten  years 
of  age.  His  ocular  history  evidenced  no  symptoms  of  particular 
interest  other  than  that  he  did  not  see  well  at  distance,  could 
not  read  his  school  books  readily,  had  had  styes  and  granular 
lids.     He  had  had  diphtheria  and  scarlet  fever  when  five  or  six 


Course  No.  14 
Page  48 

years  old.  He  had  been  a  sufferer,  so  his  mother  reported,  from 
"sick  stomach"  and  some  dizziness  and  that  this  had  come  on 
after  the  scarlet  fever.  Medical  examination  made  previous  to 
our  seeing  the  boy  had  disclosed  no  ear,  nose,  throat  or  dental 
troubles.     Tonsils  had  been  removed. 

Static  retinoscopy  disclosed:  O.  S.+0.5  D.  S.3  — -37  cyl. 
ax.  90,  O.  S.  +  i  D.  S.3  — -37  cyl.  ax.  90.  The  ophthalmometer 
showed  a  corneal  astigmatism  of  about  one-half  diopter  against 
the  rule.  Subjectively,  O.  D.+0.25  D.  S.O+0.37  cyl.  ax.  180 
and  O.  S.  +  0.5  D.  S.C+0.37  cyl.  ax.  180  gave  ¥  =  20^20.  The 
addition  of  O.  U.+0.25  D.  S.  gave  V  =  8/io  easily  but  10/10 
with  difficulty.  Dynamic  skiametry  showed  O.  U.  +  2.25  D.  S.O 
+  0.5  cyl.  ax.  180  with  "fixation  and  observation  at  the  normal 
reading  distance."  The  monocular  accommodation  tests  evi- 
denced the  fact  that  the  boy  could  not  read  No.  3  Jaeger 
(V  =  o.75  D)  at  thirteen  inches,  with  each  eye  under  test  separ- 
ately, wearing  the  distance  correction.  But  by  bringing  the 
test-type  to  within  5  inches  of  his  eye  he  could  read  the  No.  2 
type.  An  examination  of  his  pupils  showed  that  they  were  very 
constricted  and  did  not  relax  normally  in  the  dark.  The  ophthal- 
moscopic examination  showed  a  slightly  congested  nerve  head; 
it  could  have  been  passed,  however,  as  being  normal  had  all  other 
ocular  conditions  been  satisfactory.  For  reading  at  thirteen 
inches  it  was  found  that  O.  D.  +  1.5  D.  S.C+0.37  cyl.  ax.  180  and 
O.  S.-f  1.62  D.  S.3+0-37  cyl.  ax.  180  permitted  of  a  reading 
of  No.  2  Jaeger  with  a  range  of  about  a  foot  to  fifteen  inches. 
The  muscle  tests,  wearing  the  binocular  distance  correction, 
evidenced  2A  of  esophoria  and  7A  of  esophoria  at  the  reading 
point.  The  reserve  convergence  amounted,  at  thirteen  inches 
fixation,  to  some  30A. 

A  colleague  of  mine,  an  ophthalmologist,  using  atropin, 
determined  the  maximum  distance  correction  as  O.  U.  +  1.25 
D.  S. 0+0.37  cyl.  ax.  180. 

A  thorough  systemic  examination  of  the  boy  was  made  and 
he  was  put  under  medical  treatment  for  gastro-intestinal  auto- 
intoxication. We  supplied  him  for  distance  the  following  cor- 
rection: O.  D.  +  .75  D.S.C  +  .37  cyl.  ax.  iSoandO.  S.  +  .87  D.  S.C 
+  •37  cyl.  ax.  180,  and  gave  as  an  additional  pair  for  reading 
purposes  O.  D.+  1.5  D.  S.C  +  .37  cyl.  ax.  180  and  O.  S.+  1.62 
D.  S.O  +  -37  cyl.  ax.  180.  Several  examinations  made  in  the 
interim  between  initial  and  last  visit  demonstrated  that  normal 
accommodative  action  and  range  were  returning.  Today  the 
young  man  is  wearing  O.  D.  +  i  D.  S.O  +  -37  cyl.  ax.  180  and 
O.  S.+  1.12  D.  S.C  +  -37  cyl.  ax.  180  with  slightly  blurred 
distance  vision  but  with  comfort  and  ease  at  reading,  demon- 
strating some  six  to  seven  diopters  of  accommodation  under  the 
concave  lens  method  of  testing,  using  No.  2  Jaeger  type,  at 
thirteen  inches. 


Course   No.  14 
Page  49 

Illustrative  Case  B.  Miss  M.  F.,  age  ten  years,  presented 
herself  and  complained  of  incessant  headaches,  chiefly  frontal 
and  super-orbital  in  character,  which  came  on  generally  after 
being  in  school  and  in  getting  her  lessons  at  night.  Her  history 
disclosed  the  fact  that  she  had  suffered  from  typhoid  fever,  fol- 
lowed almost  immediately  by  diphtheria,  some  two  years  pre- 
vious to  our  seeing  her.  She  has  had  trouble  with  her  eyes  ever 
since.  One  of  the  young  students  in  a  clinic  made  the  following 
static  retinoscopic  and  subjective  findings.  Static  retinoscopy": 
-O.  D.  +  0.5  D.  S.C-.25  ax.  135;  O.  S.4-.75  cyl.  ax.  90. 
Subjectively,  the  binocular  tests  showed  that  O.  D.-j-O  — 0.25 
ax.  135  and  O.  S.  +  .373-I-.75  cyl.  ax.  90  gave  V  =  10/10  with 
some  difficulty.  The  comparison  tests  at  twenty  feet,  using  2A 
base  up  and  down  respectively  before  the  eyes,  disclosed  about 
equally  good  acuity  conditions.  Wearing  the  distance  correc- 
tion the  muscular  tonicity  tests  at  twenty  feet  disclosed  ortho- 
phoria both  laterally  and  vertically.  At  13  inches  the  dot  and 
line  test,  using  the  Maddox  double  prism  before  one  eye,  evi- 
denced 6A  of  es' phoria  and  slight  right  hyperphoria.  Upon 
instituting  the  tests  upon  the  amplitude  of  accommodation  it 
was  discovered  that  this  young  lady  could  not  read  No.  1  Jaeger 
tvpe  at  13  inches,  but  that  she  could  read  it  monocularly  or 
binocularly  with  a  fair  degree  of  ease  and  certainty  at  6  inches, 
the  distance  corrections  being  worn  during  these  investigations. 
The  subjective  binocular  amplitude  of  accommodation,  there- 
fore, amounted  to  7  D.  as  a  maximum  when  taken  under  the 
most  advantageous  circumstances.  By  the  concave-at-distance 
method  (see  The  Keystone  Magazine  of  Optometry^  Vol.  12, 
page  471)  there  was  disclosed  the  fact  that  the  patient  could 
not  read  any  of  the  V  =  20/20  line  through  —3  D.  S.,  the  patient 
wearing  the  static  subjective  binocular  findings,  either  monoc- 
ularly or  binocularly,  even  under  most  persistent  encouragement 
and  goading  on  the  examiner's  part.  This  demonstrated  con- 
clusively that  the  subject  under  examination  was  not  possessed  of 
more  than  a  third  to  a  half  of  the  accommodation  as  apparently 
indicated  by  the  near-point  test  and  that,  therefore,  these  near- 
point  findings  upon  the  accommodative  amplitude  were  pseudo. 
In  other  words,  this  simple  test  with  —3  D.  S.  showed,  in  the  case 
in  question,  that  the  positive  part  of  the  relative  accommo- 
dation was  abnormally  low.  Likewise  the  tests  at  the  thirteen 
inch  point  demonstrated  that,  with  convergence  constant, 
the  relation  between  the  positive  and  negative  portions  of  the 
relative  accommodation  was  such  that  accommodation  could 
not  be  comfortably  maintained.  Attention  needs  to  be  called 
to  the  important  relation  which  exists  between  these  two  parts  of 
the  relative  accommodation.  Donders  stated,  emphasizing  by 
the  use  of  italics  {Accommodation  and  Refraction  of  the  Eye^ 
page  114)  that  "The  accommodation  can  be  maintained  only  for 
a  distance  at  ivhich,  in  reference  to  the  negative  party  the  positive 
part  of  the  relative  range  of  the  accommodation  is  tolerably  great." 


Course   No.  14 
Page  50 

Howe,  in  his  "Muscles  of  the  Eye"  Vol.  i,  page  339,  writes  upon 
this  important  topic  as  follows:  "In  our  studies  of  the  patho- 
logical conditions  of  the  muscles  we  find  the  most  important  and 
apparently  the  most  frequent  anomalies  are  those  which  involve 
the  ciliary  muscle.  Therefore,  even  in  routine  examinations  and 
at  the  first  visit,  it  is  desirable  to  determine  whether  the  action 
of  that  muscle  is  normal,  or  excessive,  or  insufficient.  At  least 
a  general  idea  as  to  this  power  of  the  ciliary  muscle  is  shown  by 
placing  a  minus  3  glass  before  each  eye  and  asking  the  patient 
to  read  again  the  distant  test-type.  I  have  learned  to  regard  this 
as  oyjc  of  our  most  important  steps.  For  if,  after  the  ciliary  muscles 
have  had  a  minute  or  two  in  which  to  adjust  themselves,  the 
person  can  read  as  well  as  before,  then  we  know  at  once,  at  least 
in  a  general  way,  that  there  is  no  imperfection  in  the  power  of 
the  ciliary  muscle  apart  from  convergence.  If  the  person  cannot 
overcome  these  or  weaker  minus  glasses  in  proportion  to  his 
age  or  in  proportion  to  the  ametropia,  then  we  at  once  suspect 
some  insufficient  power  of  the  ciliary  muscles.  Even  when  such 
insufficient  accommodation  does  exist,  there  may  be  little 
or  no  discomfort  at  near  work,  especially  if  the  extraocular 
muscles  are  exceptionally  strong  or  the  general  condition  or  the 
occupation  of  the  individual  unusually  favorable.  But  ordinarily 
if  the  positive  part  of  the  relative  accommodation  (note  by 
present  writer:  this  is  tested  through  the  use  of  minus  lenses) 
is  insufficient  with  parallel  axes,  and  also  with  convergence  at 
one-third  of  a  meter,  and  if  discomfort  and  headache  do  exist, 
then  that  clue  should  be  followed  up.  The  examinations  should 
be  repeated  at  first  roughly,  if  desired,  with  convergence  at 
one-half  or  one-quarter  of  a  meter.  But  if  this  evidence  points 
in  the  same  direction,  and  if  the  discomfort  continues  even  when 
other  possible  causes  of  the  difficulty  are  eliminated,  then  it  is 
usually  worth  while  to  make  the  data  more  complete 
Of  late  years  American  ophthalmologists  particularly  have 
taken  great  pains  to  determine  the  condition  of  the  extraocular 
muscles  and  have  been  so  engrossed  with  these  alone  that  physi- 
ological facts  concerning  the  intraocular  muscles  which  were 
demonstrated  long  ago  and  which  are  still  of  the  utmost  impor- 
tance have  been  forgotten." 

Dynam'c  skiametry,  with  fixation  and  observation  at  13 
inches,  indicated:  O.  b.  +  2.75  D.  S.^  — -37  ^^-  ^3S  ^^^  O-  S. 
-i-2.5  D.  S.3  +  -75  ^^-  9°-  These  lens  quantities  represent  the 
totals  inserted  before  the  eyes  in  order  to  obtain  neutral  shadows. 
The  skiascopic  shadows  were  rather  erratic  in  this  case  and  are 
worthy  of  more  than  passing  comment.  With  the  static  retin- 
oscopic  findings  inserted  before  the  eyes,  initially,  the  shadows 
were  decidedly  "with."  The  addition  of  O.  U.-I-0.5  D.  S.  pro- 
duced for  the  moment  neutrality  of  motion  only  to  give  way  to 
a  "with"  motion,  ultimately  made  neutral  by  means  of  the 
lenticular    findings    recorded    in    the    opening    sentence    of   this 


Course   No.  14 
Page  51 

paragraph.  There  is  some  evidence,  therefore,  of  ciliary  spasm 
from  the  behavior  of  the  skiascopic  shadows,  for  apparently  a 
condition  of  neutrality  gave  way  to  indications  of  further  cor- 
rigible hyperopia  or  further  demands  on  the  part  of  the  accom- 
modation as  the  lenticular  assistance  offered  to  the  ciliary 
in  the  interests  of  relaxation  progressed.  From  the  evidence  as 
gathered  from  all  possible  tests  the  writer  is  of  the  opinion  that 
the  major  portion  of  the  added  spherical  power  found  by  the 
dynamic  method  was  in  the  interest  of  alleviating  a  ciliary  spasm 
and  in  aiding  an  impaired  and  insufficient  lenticular  action; 
largely,  however,  the  former  of  the  two. 

Tests  upon  the  positive  and  negative  reserve  convergences 
as  well  as  duction  tests  at  twenty  feet  indicated  that  there  were 
no  muscular  derangements  or  innervational  defects  of  a  character 
to  influence  or  interfere  with  the  accommodative  action.  The 
patient,  irrespective  of  her  age  (10  years),  was  given  prescrip- 
tions for  two  pair  of  glasses,  one  for  distance  wear  and  one  for 
reading.  For  distance  we  gave  O.  D.  +  1.25  D.  S-C" -25  ax. 
135  and  O.  S.  +  1.25  D.  S.C--75  ax.  180,  giving  V  =  8/io  with 
some  difficulty.  For  reading  she  was  given  O.  D.-(-2  D.  S.3 
-.25  ax.  135  and  O.  S.  +  2.25  D.  S.C-.75  ax.  180.  These 
latter  gave  a  visual  acuity  binocularly  of  6/10  at  best.  The 
subjective  accommodative  tests  at  13  inches  demonstrated  that, 
equipped  with  the  reading  correction,  she  could  read  No.  2 
Jaeger  with  some  degree  of  ease  and  that  her  range  extended 
from  7  inches  to  18  inches.  The  patient  was  instructed  to  wear 
the  distance  glasses  constantly  except  during  study  hours  or 
other  periods  of  close  work,  when  the  reading  glasses  were  to  be 
substituted.  This  she  did  for  a  period  of  six  months.  A  re- 
examination at  the  end  of  that  time  showed  that  her  distance 
correction  could  be  increased  and  that  the  accommodative  reserve 
at  thirteen  inches  had  increased  to  about  2  D.  in  each  eye,  thus 
indicating  an  accommodative  amplitude  of  5  D.  The  head- 
aches had  entirely  disappeared.  We  gave  her  at  this  second 
examination  O.  D.-f  1.75  D.  S.C--^5  ax.  135  and  O.  S.-f-2  D.  S. 
3  — .62  ax.  180  for  constant  wear.  These  have  proven  entirely 
satisfactory,  although  they  did  not  afford  for  a  few  weeks  after 
their  prescription  an  acuity  quite  equal  to  V  =  8    10. 

IV.     Dynamic  Cross-Cylinder  Method 

The  late  R.  M.  Lockwood  wrote  many  deliqhtful  articles 
upon  many  scientific  subjects.  None  of  those  have  been  of  more 
interest  to  the  writer  than  his  papers  on  "Cylinders  and  Cross 
Cylinders,"  appearing  in  the  Optical  Journal.  We  feel  that,  in 
discussing  the  dynamic  cross-cylinder  method,  we  cannot  improve 
upon  Lockwood's  very  clear  presentation.  We  are  therefore 
quoting  at  length  from  one  of  his  papers.  {Optical  Journal^ 
Vol.  43,  page  955,  1919.) 


Course  No.  14 
Page  52 

"When,  as  a  result  of  our  tests,  an  eye  has  been  made  emme- 
tropic by  means  of  lenses,  and  attention  is  paid  to  the  type  on 
the  near  chart,  there  passes  an  impulse  from  the  retina  to  the 
brain  as  the  result  of  which  there  comes  back  a  return  impulse 
which  innervates  the  ciliary  muscle,  and  causes  that  muscle  to 
so  alter  its  tension  that  the  object  of  attention  is  focused  more 
or  less  well  on  the  retina.  If  this  innervation  is  not  just  right, 
it  is  quite  conceivable  that  other  corrective  efforts  follow,  and 
that  in  the  end  the  best  attainable  image  possible  for  that  eye 
is  had,  or  else  there  is  a  compromise,  the  innervation  resulting 
in  a  focus  that  is  slightly  imperfect  or  blurred,  because  such 
an  imperfection  is  less  irritating  than  the  extra,  exact  inner- 
vation  of  the   ciliary   necessary    to   reduce   the   imperfection. 

"Suppose  that  a  certain  eye  is  being  used  at  a  distance  of 
16  inches,  but  the  near-point,  (wearing  the  full  distance  cor- 
rection) is  only  at  18  inches;  this  is  clearly  a  case  of  insufficient 
accommodation;  the  near-point  might  be  even  closer,  and  yet 
with  due  regard  to  the  need  of  reserve  accommodation  there 
would  still  be  an  insufficiency.  But  take  another  case  where 
the  patient  is  young,  and  the  near-point  at  eight  inches,  say; 
and  yet  when  the  eyes  are  used  at  a  distance  of  16  inches  the 
accommodation  falls  short  because  of  a  faulty  innervation  to  the 
ciliary  muscle.  Such  a  case  is  not  presbyopic;  it  is  one  of 
inefficiency  of  the  accommodation,  or  pseudo-presbyopia.  In 
either  case  the  extra  plus  that  must  be  put  before  the  eye  to  cause 
the  innervation  to  act  just  right  so  that  focusing  is  neither  under 
nor  over  is  some  sort  of  a  measure  of  the  dynamic  error  in  the 
accommodation.  To  get  this  measure  in  each  and  every  case 
and  incidentally  to  discover  how  much  accommodation  must  be 
kept  in  reserve  in  order  to  have  theoretically  perfectly  comfortable 
vision  for  near,  we  use  the  cross-cylinder  dynamic  method. 


Figure  4. — Lockwood's  Chart  for  Use  in  the  Dynamic  Cross- 
Cvlinder  Method. 


Course   No.  14 
Page  53 

"If  the  refractive  error  in  a  given  eye  has  been  determined, 
and  this  has  been  checked  on  the  near  chart  to  see  that  near 
vision  is  clear  and  sharp,  then  by  placing  before  that  eye  a 
compound  equivalent  to  a  cross-cylinder,  say  the  C  compound 
(  +  0.50  sph.3~i-  cyl.)  we  will  create  a  false  astigmatism  which 
results  in  one  principal  meridian  being  made  hypermetropic  and 
the  other  myopic  to  the  same  amount.  If  the  eye  is  looking  at 
the  test-type  at  the  time  the  type  will  be  blurred  but  if  the  fixa- 
tion object  is  a  T  chart  (Fig.  4)  and  the  arms  of  the  T  are  made 
to  agree  with  the  principal  meridians  of  the  false  astigmatism, 
then,  if  before  applying  the  test  the  eye  was  in  exact  focus, 
there  will  be  no  perceptible  difference  in  the  clearness  of  the 
two  sets  of  lines.  If  the  tocus  was  not  exact,  then  the  test  will 
show  a  difference,  and  the  spherical  part  of  thejcorrectionfmust 
be  altered  until  the  difference  does  not  show." 

The  technique  of  the  method  may  be  tried  out  as  follows: 
(i)     Set  up  the  full  distance  correction   and,  if  necessary 

for  clear  vision,  (presbyopic  cases)  add  sufficient  plus  spherical 

power  for  the  purpose. 

(2)  Arrange  the  fixation  card  (Fig.  4)  on  a  stand  or  in  a 
holder  so  that  the  sets  of  lines  are  truly  horizontal  and  vertical 
(other  directions  can   be  used  if  preferred). 

(3)  Have  ready  a  +0.50  sph.Q— i-  cyl.  testing  compound 
(equivalent  to  a  cross-cylinder),  minus  marks  held  to  exactly 
agree  in  direction  with  the  arms  of  the  T  testing  chart.  Drop 
the  same  in  front  of  the  distance  correction  and  have  the  patient 
announce  whether  both  sets  of  lines  are  seen  equally  clear,  or 
whether  there  is  a  difference.  If  there  is  a  difference,  and  the 
lines  agreeing  in  direction  with  the  minus  cylinder  marks  are 
clearest,  the  spherical  power  in  the  frame  must  be  made  less 
plus,  etc.,  until  there  is  a  balance.  The  extra  plus  that  must 
be  added  to  the  distance  full  correction  to  get  perfectness  of 
focus  is  a  measure  of  the  accommodative  error. 

"The  above  will  apply  to  all  cases  where  the  contraction  of 
the  pupils  tor  near  vision  does  not  produce  a  change  in  the 
cylindrical  finding,  which  should  be  made  before  the  dynamic 
test  is  tried. 

"Insufficiency  of  accommodation  is  far  from  uncommon  in 
young  eyes,  and  should  be  looked  for  in  every  case,  though  there 
is  a  difference  of  opinion  as  to  what  should  be  done  with  it  when 
found.  Some  say  that  nothing  should  be  done;  that  the  full 
correction  of  the  refractive  error  will  make  the  eye  normal, 
and  that  an  eye  made  normal,  barring  presbyopia,  will  function 
perfectly.  Others  hold  that  whatever  defect  of  accommodation 
is  determined  by  the  cross-cylinder  dynamic  method  shall  be 
fully  corrected  regardless  of  age.  Still  others  say  the  dynamic 
findings  should  be  taken  into  consideration  and  if  the  symptoms 
warrant  it,  there  should  be  plus  help  for  near.  Personally,  I 
(Lockwood)  favor  this  latter  view. 


Course  No.  14 
Page  54 

"Example  i.  Refractive  error  is  corrected  by  +1.  sph.O 
+  1.  cyl.  180°.  Checked  up  for  near  vision,  the  cylinder  finding 
remains  unchanged;  punctum  proximum  is  at  eight  inches. 
Using  the  dynamic  cross-cylinder  method  an  extra  +0.75  sphere 
is  needed  to  get  perfect  focus.  Glasses  have  never  been  worn 
before,  and  there  are  no  headaches;  only  decreased  visual 
acuity.  In  this  case  the  +1.  sph.^i-  cyl-  ax.  180  corrects  the 
distance  error;  also  corrects  most  of  the  near  error,  so  it  can 
be  given  for  constant  wear. 

"Example  2.  Distance  correction  is  +0.25  sphere;  no 
astigmatism,  far  or  near;  dynamic  cross-cylinder  method  indi- 
cates that  +1.25  must  be  added  to  get  perfect  focus  at  the 
reading  distance.  No  trouble  in  distance  vision,  but  headaches 
and  swimming  of  letters  in  near  work  after  an  hour  or  so;  punc- 
tum proximum  73'2  inches.  By  the  old  methods,  the  prescrip- 
tion would  be  +0.25  sph.  for  constant  wear.  I  would  favor 
instead  +1.  sphere  for  close  work,  no  glasses  for  distance,  etc." 

The  cross-cylinder  dynamic  test  can  be  used  to  differentiate 
between  the  forced  and  comfortable  amplitude  of  accommoda- 
tion. To  this  end  there  should  be  a  set  of  T  charts,  say  three  of 
them,  one-half  the  size  of  that  shown  in  iMg.  4,  one  the  same 
size  and  one  of  twice  the  size.  After  the  full  distance  correction 
has  been  determined  and  put  before  the  eye  under  test  the 
cross-cylinder  is  added  to  it  and  the  smallest  T  chart  brought 
close  to  the  eye  and  slowly  withdrawn  until  both  lines  come 
equally  clear.  If  this  does  not  happen  by  the  time  a  distance 
of  12  inches,  say,  is  reached,  the  second  sized  T  chart  should 
be  substituted  out  to  about  24  inches,  and  then  the  large  T  chart 
used  up  to  about  40  inches,  until  the  point  of  equalization  is 
found.  Converted  into  diopters  we  get  the  amplitude  of  com- 
fortable accommodation.  If  the  equalizing  point  is  still  farther 
away,  we  increase  the  sphere  in  the  frame  by  i.  D.  and  repeat 
the  test  making  allowance  in  the  calculation  for  the  i.  D.,  etc. 
The  forced  accommodation  is  found  in  any  of  the  usual  ways. 
By  comparing  the  two  results  we  get  an  idea  of  how  much 
(theoretically)  accommodation  should  be  kept  in  reserve  in 
the  given  case. 

"Example  3.  With  distance  correction  in  place  the  punctum 
proximum  found  in  the  usual  way  is  at  seven  inches  which  equals 
5.75  D.  amplitude.  The  P.  P.  found  by  the  dynamic  cross- 
cylinder  test  is  at  ten  inches  which  equals  4.  D.  The  reserve 
accommodation  in  this  case  should  be   1.75  D. 

"Example  4.  The  amplitude  of  accommodation  found  in  the 
usual  way  is  7.  D.  By  the  cross-cylinder  dynamic  test  alone  the 
comfortable  near-point  cannot  be  located.  Adding  a  plus  i.  D. 
to  correction  it  is  now  located  at  26  inches.  This  distance 
equals  1.50  D.;  making  allowance  for  the  extra  i.  D.  this  is 
reduced  to  0.50  D.    Hence  in  this  case  for  perfect  comfort  there 


Course  No.  14 
Page  55 

should  be  a  reserve  of  6.50  D.  which  is  markedly  in  excess  of  the 
usual   average  of  one-third   to  one-half." 


V.     Objective    Method     of    Determining     the     Amplitude 
of  Accommodation 

In  1917  the  writer  proposed  an  objective  method  of  deter- 
mining amplitudes  of  accommodation.  The  essential  optical 
principles  underlying  these  tests  are  those  involved  in  skiametry 
and  the  applications  of  the  laws  ot  conjugacy  of  foci. 

•"^N^  Figures  5,    6    and    7  show  diagrammatically  the 

general  modus  operandi  in  the  monocular  method. 
Each  eye  should  be,  in  turn,  occluded  and  its  ac- 
commodative range  investigated,  since  some  of  the 
most  interesting  and  important  cases  from  the 
ocular  economic  standpoint  are  those  involving 
marked  differences  between  the  acommodative  re- 
sources of  the  two  eyes. 

In  practice  matters  are  so  arranged  that  the 
object  viewed  (Fig.  5)  shall  be  reasonably  illu- 
minated. The  Hooding  of  the  room  with  artificial 
light,  if  this  be  by  indirect  or  semi-indirect  methods 
of  lighting,  is  not  objectionable  except  from  the  opera- 
tor's standpoint.  With  experience,  however,  one  can 
use  retinoscopic  methods  and  follow  the  reflexes  with 
ease  and  accuracy  under  almost  any  subdued  lumin- 
ous surroundings.  The  writer  invariably  uses  the 
self-luminous  instrument  in  these  tests. 

The  patient  is  given  a  line  of  type  printed  in 
about  10  or  12  point  type  upon  a  card  about  one- 
quarter  inch  wide  and  fastened  to  some  convenient 
holder  such  as  illustrated  in  Figure  5.  Or  a  single  line 
ruled  on  a  card  or  a  pencil  will  serve  satisfactorily 
as  a  fixation  object,  but  there  is  not  the  incentive  to 
full  accommodation  as  when  reading  is  demanded.  The 
full  monocular  distance  finding,  affording  as  nearly 
V  =  20/20  as  possible,  is  inserted  before  the  eye  to 
be  tested.  The  patient  is  then  given  the  test  object— 
which  he  holds  initially  at  about  13  inches  —  and  is 
told  to  read  the  letters.  Or  the  operator  may  hold 
the  test  object  in  one  hand  and  approach  it  toward 
the  patient.  In  general  we  have  the  patient  hold  the 
card  slightly  to  the  nasal  side  during  the  examination 
of  either  eye  while  we  proceed  to  examine  skiamet- 

rically  from  the  temporal  side   and   as  close  to  the   visual   line 

as  possible. 


Course   No.  14 
Page  56 


Figure  6. — The  Optical  Principles  involved  in  the  Objective  Test  for  the 
Amplitude  of  Accommodation. 

In  Figurfe  6  there  is  represented  the  optical  and  ocular 
conditions  present  when  the  retina  and  the  object  viewed  are 
conjugate  points  and  the  exact  or  requisite  number  of  diopters 
of  accommodation  demanded  for  the  point  fixed  are  supplied. 
Under  these  conditions,  therefore,  with  the  accommodative 
point  kept  constant  at  F  and  the  mirror  A  in  the  same  plane  a 
neutral  shadow  condition  should  obtain  and  by  moving  the 
retinoscope  to  C — an  inch  nearer  the  eye  —  a  hyperopic  con- 
dition should  be  revealed  or  by  withdrawing  an  inch  farther 
from  the  eye,  as  at  5,  a  myopic  condition  should  be  evidenced. 
By  then  moving  or  having  the  patient  move  the  test-object 
nearer  the  eye  the  actual  near-point  will  be  found  as  soon  as  the 
retinoscopic  mirror  has  to  be  operated  in  a  plane  back  of  the 
fixation  point  in  order  to  obtain  a  neutral  shadow.  These 
are  ideal  conditions  in  that  we  are  assuming  a  perfectly  inner- 
vated and  functioning  ciliary  and  lenticular  action,  and  that 
there  is  no  lag  of  accommodation  behind  convergence  as  dis- 
cussed elsewhere.  {Vide  Sheard:  Dynamic  Skia7netry,  1920.) 
In  short,  we  are  here  writing  of  ideal  and  physically  perfect 
conditions. 

In  general,  however,  it  is  found  that  when  the  patient, 
wearing  the  full  distance  correction,  reads  monocularly  the  letters 
(which,  by  the  bye,  may  be  as  small  as  the  patient  can  see), 
there  is  a  "with"  or  hyperopic  motion  —  using  the  plane  mirror  -- 
indicating  that  the  point  conjugate  to  the  retina  in  the  eye  opti- 
cally statically  perfect  is  not  at  the  position  of  the  object  viewed 
but  at  a  point  somewhat  behind  that  point,  /.  e.,  farther  from 
the  eye.  In  Figure  7A,  let  F  be  the  point  viewed  and  A  the 
position  of  the  operator's  mirror.  If  a  certain  test  shows  that 
DF  is  10  inches  (4D)  and  DA  is  13  inches  (3D)  we  should  con- 
clude that  the  accommodation  actually  available  at  ten  inches 
is  sufficient  only  for  the  optical  conjugacy  at  13  inches,  hence 
indicating  the  need  of  a  diopter  of  lenticular  assistance.  We 
must,  however,  bear  in  mind  the  probable  physiological  lag  of 
accommodation  which  amounts,  in  the  average  case,  to  about 
one-half  diopter.     By  approaching  the  object  closer  and  closer 


Course   Xo.  14 
Page  57 


CAB 


Figure  7A. — Illustrating  the  Procedure  in  Obtaining  Skiametric  Determinations 
of  the  Amplitude  of  Accommodation. 


to  the  eye  a  point  will  finally  be  found  such  that  no  nearer 
approach  of  the  test-object  to  the  eye  changes  the  neutral 
condition  of  reflex  as  skiascopically  observed  at  the  closest 
point  to  the  eye  at  which  a  neutral  shadow  is  obtained. 

In  testing,  therefore,  for  the  near-point  objectively  we 
proceed  as  follows:  The  patient  draws  the  test-object  as  near 
the  eye  as  will  still  permit  of  its  reading.  To  the  observer  at 
thirteen  inches  the  skiascopic  reflex  will  show  an  "against"  or 
myc  pic  condition  indicating  that  he  is  outside  of  the  optical 
ocular  far-point  dynamically  considered.  The  operator  then 
moves  forward  until  he  obtains  the  neutral  shadow  position. 
The  test-object  is  then  to  be  carried  still  closer  to  the  eye  (blurred 
images  make  no  difi^erence)  and  the  nearest  point  of  neutral 
shadow  found  and  measured.  This  gives  the  apparent  near- 
point  under  whatever  ocular  conditions  the  test  is  made  (ordi- 
narily when  wearing  the  distance  correction)  and  from  it  the 
range  and  amplitude  of  accommodation  are  easily  determined. 
We  measure  the  distance  DA  (Figure  7A)  and  not  FD.  We 
occasionally  vary  this  test  and,  with  observation  and  fixation  at 
thirteen  inches,  produce  neutralization  of  shadow  at  this  point 
and  then  proceed  as  outlined  above.  We  are,  however,  partial 
to  the  test  in  which  the  static  finding  is  worn. 

The  method  is  certainly  very  simple  and  quickly  carried  out. 
The  question  arises:  Are  there  any  inherent  errors?  Yes; 
those  of  observation  and  ot  optical  imperfections,  lack  of  response 
on  the  part  of  the  person  under  test,  and  the  difficulties  of  making 
accurate  measurements  of  distances.  For  this  latter  purpose  we 
use  a  light-weight,  narrow  tape-measure,  one  end  fastened  to 
the  trial  frame  with  due  allowance  for  distance  from  the  cornea, 
and  the  other  end  weighted,  the  tape  when  in  use  being  carried 
between  the  finger  and  thumb  of  the  hand  holding  the  retin- 
oscope. 

These  tests  must  certainly  suggest  themselves  to  the  reader 
as  being  most  valuable,  especially  in  finding  the  range  and 
amplitude  of  accommodation  in  children   (for  one  can  employ 


Course   No.  14 
Page  58 


Figure  7B. — Illustrating  the  Procedure  in  Obtaining  Skiametric  Determinations 
of  the  Amptitude  of  Accommodation. 


some  colored  pictures  pasted  on  the  rear  side  of  the  test-object 
shown  in  Figure  5);  in  presbyopia;  in  subnormal  accommoda- 
tion; in  excessive  accommodation;  in  amblyopia,  when  we 
are  uncertain  whether  or  not  accommodation  is  still  active 
because  of  the  uncertainty  of  subjective  tests  by  virtue  of  the 
reduced  visual  acuity,  and  in  anisometropia. 

Likewise  we  are  provided  with  an  objective  method  which 
tells  us  whether  or  not  accommodation  is  proportionately 
enforced  in  those  rather  frequent  cases,  already  alluded  to,  in 
which  the  patient,  usually  young  in  years,  is  not  able  to  read 
fine  print  at  fourteen  inches  but  can  read  it  when  brought  up 
very  close  to  the  eye.  Our  answer  is  that  these  tests  demon- 
strate the  universality  of  lack  of  proportionate  accommodative 
action  and  that  such  type  is  read  at  points  abnormally  close 
to  the  eye  because  of  increased  sizes  of  retinal  images,  con- 
striction of  pupil   and  narrowing  of  the  palpebral   fissure. 

Furthermore,  these  objective  tests  show  that  the  ampli- 
tudes of  accommodation  are  in  closer  agreement  with  the  results 
tabulated  in  a  preceding  section  under  the  concave-at-near 
method  than  they  are  with  monocular  near-points  and  binocular 
concave-at-distance  methods. 


Course  No.  14 
Page  59 

Chapter  IV. — Anomalies  of  Accommodation 

Having  briefly  outlined  some  of  the  salient  anatomical  and 
physiological  facts  relative  to  the  accommodative  apparatus  of 
the  eye  and  having  pointed  out  the  fact  that  contraction  of  the 
ciliary  muscle  and  that  of  the  sphincter  of  the  pupil  are  almost 
always  simultaneously  exerted  while  relaxation  of  the  accommo- 
dation is  usually  accompanied  by  dilatation  of  the  pupil,  and, 
in  addition,  having  called  attention  to  the  basic  principle  that  the 
"capital  symptom  of  an  anomaly  of  the  accommodation  is  the 
change  in  position  of  the  punctum  proximum  or  of  the  punctum 
remotum,  as  well  as  the  visual  disturbances  resulting  from  it" 
(Landolt),  we  pass  on  to  consider  what  Bonders  has  entitled, 
in  his  classic  work  on  The  Accotnmodation  and  the  Refraction 
of  the  Eye,  morbid  paralysis  of  accommodation.  We  are  taking 
the  liberty  of  quoting  verbatim  upon  this  topic  from  the  writings 
of  this  celebrated  writer,  who  was,  during  his  lifetime,  the  pro- 
fessor of  physiology  and  ophthalmology  in  the  University  of 
Utrecht.  We  may  be  pardoned  for  so  doing  because  these 
writings  are  rather  difficult  to  secure  and  hence  are  not  available 
to  many  students  and  practitioners  and  for  the  further  reason 
that  our  store  of  information  upon  paralysis  and  paresis  of 
accommodation  has  not  been  greatly  increased  since  the  time 
of  Bonders.  (The  year  1864  marks  the  appearance  of  his  treatise 
on  The  Accoinmodation  and  Refraction  of  the  Eye.)  At  least 
many  of  the  fundamental  and  essential  points  relative  to  the 
paresis  and  paralysis  of  accommodation  are  included  in  the 
essay  from  which  we  shall  quote. 

Paralysis  of  Accommodation 

"Paralysis  of  accommodation  as  disease  is  by  no  means  an 
unusual  occurrence.  Emmetropic  and  ametropic  eyes  are  alike 
liable  to  it.  It  occurs  too  at  every  age,  but  in  old  persons,  who 
have  already  lost  there  accommodation  by  senile  changes,  it  is 
of  little  importance.  As  we  know  that  the  accommodation  is 
effected  exclusively  by  the  internal  muscles  of  the  eye,  we  can 
seek  paralysis  also  only  in .  the  fibers  of  the  short  root  of  the 
ciliary  ganglion.  Now,  in  fact,  it  often  happens  that  only  these 
fibers  are  paralyzed,  and  in  this  case  we  have  paralysis  of  accom- 
modation alone;  except  that  paralysis  of  the  sphincter  pupillae, 
which  derives  its  motor  fibers  from  the  same  root,  is  usually 
combined  therewith.  But  in  about  an  equal  number  of  cases 
there  exists  at  the  same  time  paralysis  of  other  fibers  of  the 
oculo-motor  nerve,  and  not  infrequently  the  paralysis  extends 
even  to  all  branches  of  this  nerve.  It  is  remarkable  that  while 
paralysis  of  accommodation  very  often  occurs  separately, 
paralysis  in  the  domain  of  the  oculo-motor  nerve  is  comparatively 
rarely  met  with,  without  paralysis  of  accommodation.  I  may 
add  that,  so  far  as  my  experience  goes,  uncomplicated  paralysis 
of   accommodation    occurs    much    more    frequently    in    women, 


Course  No.  14 
Page  60 

often  too  in  children;  paralysis  of  the  oculo-motor  nerve  on  the 
contrary,  including  paralysis  of  the  accommodation,  is  much 
more  frequently  found  in  men  and  ordinarily  not  until  after 
the  twenty-fifth  year.  In  either  case,  the  paralysis  is  rarely 
complete;  generally  speaking,  it  is  only  paresis,  inasmuch  as 
a  certain  though  usually  only  a  slight  degree  of  accommodation 
has  remained. 

"Uncomplicated  paralysis  of  accommodation  has  only  one 
objective  symptom:  Dilatation  and  immobility  of  the  pupil. 
The  dilatation  is  not  considerable,  tor  even  with  complete 
paralysis  a  wider  pupil  than  the  normal  in  the  dark  is  not  to  be 
expected.  Nevertheless,  in  complete  paralysis  not  a  trace  of 
either  accommodative  or  of  reflex  movement  is  to  be  seen.  But 
I  may  add  that  these  cases  are  extremely  rare.  Further,  the 
connection  between  paralysis  of  the  pupil  and  of  accommoda- 
tion cannot  be  called  absolute;  once  I  found  satisfactory  accom- 
modation still  co-existent  with  absolute  immobility  of  the  pupil. 
In  one  instance,  too,  paralysis  of  accommodation  disappeared 
without  a  return  of  the  mobility  of  the  pupil,  and,  on  the  other 
hand,  with  perfect  or  almost  perfect  loss  of  accommodation, 
the  motion  of  the  pupil  may  be  but  little  disturbed." 

Errors  of  Refraction  in  Their  Relation  to  Paresis  and 
Paralysis  of  Accommodation 

"From  all  this  it  is  evident  that  the  subjective  phenomena 
are  the  most  important.  Now,  upon  these  the  refraction  of  the 
eye  has  a  considerable  influence. 

"Myopes  whose  farthest  point  is  not  more  than  fourteen 
inches  from  the  eye  find  no  difficulty  in  reading,  for  this  point 
remains  unchanged,  and  although  their  nearest  point  then 
coincides  with  it,  they  see,  with  unalterable  refraction,  per- 
fectly acutely  at  the  distance  of  fourteen  inches  or  less.  The 
disturbance  is  confined  to  this,  that,  on  the  one  hand,  objects 
at  a  greater  distance  appear,  on  account  of  the  greater  circles  of 
diffusion  of  the  larger  pupil,  more  diffuse  than  usual  —  on  the 
other,  that  within  the  distance  of  their  combined  nearest  and 
farthest  point,  they  cease  to  see  acutely.  Both  disadvantages 
are  in  great  part  removed  when  the  paralysis  of  accommoda- 
tion is  incomplete,  and  we  then  hear  a  very  few  complaints  from 
myopes.  It  is  only  when  they  wear  neutralizing  spectacles, 
and  use  them  at  their  work,  that  they  are  on  a  footing  with 
emmetropes. 

"Ernmetropes.  —  These,  on  the  occurrence  of  paralysis  of 
accommodation,  immediately  resort  to  the  'oculist.'  They  can 
no  longer  read  nor  write,  and  they  are  aware  that  an  important 
disturbance  exists;  even  when,  as  is  usual,  only  one  eye  is 
affected,  a  certain  dimness  is,  on  account  of  the  acute  origin  of 
the  paralysis,  forthwith  observed,  causing  each  eye  to  be  sep- 
arately tried,  and  thus  the  lesion  is  discovered.  (Note  by  present 
writer:      How   often,    however,    have    practitioners    found    that 


Course   No.  14. 
Page  61 

this  dimness  is  not  discovered  by  the  patient  and  no  simple 
tests  such  as  that  involving  the  comparision  of  the  eyes  by 
trying  each  separately  is  ever,  apparently,  conceived  of  by  the 
patient.)  If  we  find  that  vision  at  a  distance  is  acute,  and  with 
either  concave  or  convex  glasses  becomes  diffuse,  while  for  near 
objects  convex  glasses  are  necessary,  the  diagnosis  is  made  which 
finds  only  a  still  further  confirmation  in  the  torpidity  of  the 
dilated  pupil. 

"The  paralysis  of  accommodation  is  productive  of  yet 
greater  disturbance  in  hypermetropes:  not  only  for  near,  but 
also  for  distant  objects,  with  respect  to  which  an  involuntary 
accommodation  formerly  overcame  their  hypermetropia,  is  their 
vision  diflFuse.  It  is  evident  that  such  a  condition  suggests  the 
idea  of  amblyopia.  ...  By  attending  to  the  direction, 
in  any  disturbance  of  vision,  systematically  to  define  with 
glasses  the  refraction,  and  the  acuteness  of  vision  in  distant 
vision  we  shall  be  sure  to  avoid  error;  amblyopia  is  thereby 
forthwith  excluded,  and  while  the  glasses  required  for  distant 
vision  are  insufficient  for  seeing  near  objects,  the  paralysis  of 
accommodation  is  recognized. 

"The  phenomena  are  less  characteristic  when  no  complete 
paralysis  but  only  paresis  is  present.  The  myope  then  often 
experiences  no  actual  disturbance;  the  emmetrope  complains 
ot  fatigue  only  on  tension  for  near  objects,  resembling  the 
asthenopia  of  the  hypermetrope;  but  the  hypermetrope  very 
rapidly  experiences  considerable  asthenopia  for  near  objects, 
and  even  difficulty  in  seeing  acutely  at  a  distance.  In  general, 
with  paresis  of  accommodation,  asthenopia  very  quickly  occurs; 
in  the  first  place,  because  the  wider  pupil  requires  more  accurate 
accommodation  to  distinguish  satisfactorily;  in  the  second 
place,  because,  just  as  in  atropia-paresis,  the  relative  range  of 
accommodation  is  very  unfavorably  situated;  while  with  the 
maximum  convergence,  the  closest  point  is  found  comparatively 
little  farther  from  the  eye;  with  medium  convergence,  only  a 
slight  tension  of  accommodation  appears  to  be  possible  — 
sometimes  in  paresis  of  accommodation  micropia  is  also  com- 
plained of.      .      .      . " 

Treatment    of    Paresis    and    Paralysis    of    Accommodation 

Bonders  discusses  at  this  point  methods  ot  treatment  tor 
paresis  and  paralysis  of  accommodation.  Much  of  this  is  doubt- 
less antiquated  and  superseded  by  the  modern  rnethods  and 
practices  of  refraction  and  medicine.  The  foregoing  citations 
from  Donders  and  others  of  a  similar  nature  which  might  be 
quoted  from  various  ophthalmological  treatises  and  encyclo- 
pedias should  serve  to  call  the  attention  ot  all  eye  practitioners  to 
the  condition  of  paresis  and  paralysis  of  the  accommodation 
only  or  of  the  oculo-motor  system  and  the  probable  symptoms 
and  evidences  of  the  presence  thereof.     These  remarks  should 


Course   No.  14 
Page  62 

further  serve  to  put  the  refractionist  on  his  guard  lest  he  fail  to 
fully  conserve  the  interests  and  possible  longevity  of  his  patient 
by  failure  to  diagnose  paretic  and  semi-paralytic  conditions. 
Skill  and  thorough  knowledge  are  needed  in  order  to  differentiate 
between  cases  demanding  refractive  treatment  or  assistance 
solely  and  those  demanding  all  possible  sources  of  help,  both 
medical  and  non-medical.  It  may  be,  with  propriety,  very 
bluntly  pointed  out  here,  that  the  human  race  is  said  to  be 
permeated  and  ravaged  with  syphilis  through  the  sins  of  the 
sons  as  well  as  of  the  fathers  "even  unto  the  third  and  fourth 
generations"  back.  Perhaps  it  is  true  that,  too  often,  apparently 
unsolvable  ocular  conditions,  reduced  acuity,  weakened  accom- 
modation and  convergence  are  laid  at  the  door  of  this  disease  for 
want  of  a  better  or  more  accurate  diagnosis.  Yet,  it  is  true, 
that  many  of  these  paretic  conditions,  especially  those  involving 
accommodation  and  convergence,  are  attributable  to  primary 
or  inherited  ^syphilis.  It,  therefore,  behooves  all  practitioners 
upon  the  eye  to  carefully  investigate  the  powers  and  resources 
of  the  accommodation  as  well  as  other  ocular  functions.  In 
nervous  conditions  all  optical  assistance  possible  should  be 
afforded,  but,  as  Bonders  says,  "where  the  nervous  system  is 
more  generally  implicated,  regimen  and  treatment  are  directed 
to  that  condition,  without  special  attention  to  the  paralysis  of 
accommodation." 

We  close  this  series  of  quotations  upon  the  morbid  paralysis 
of  accommodation  as  taken  from  Bonders  by  quoting  that 
paragraph  from  his  writings  which  deals  with  the  optical  treat- 
ment. While  his  remarks  are  rather  indefinite,  yet  they  bring 
to  our  attention  suggestions  which  are  eminently  worth  while 
and  deserving  of  some  personal  thinking.  He  says:  "Respecting 
the  use  of  spectacles  in  paralysis  of  accommodation,  it  is  almost 
sufficient  to  observe  that  there  is  scarcely  ever  any  objection 
to  bringing  the  point  of  distinct  vision  to  the  distance  which 
the  existing  acuteness  of  vision  and  the  nature  of  the  work  to  be 
performed  render  desirable.  Sometimes,  however,  especially 
when  the  paralysis  is  incomplete,  we  give  weaker  glasses,  so  that 
the  tension  required  ensures  practice  of  accommodation.  But 
if  asthenopia  then  occurs,  we  do  not  withhold  stronger  glasses. 
Whether  in  paralysis  of  accommodation  of  one  eye  the  assist- 
ance of  a  convex  glass  is  to  be  afforded  must  be  judged  from 
what  has  been  said  as  to  the  use  of  glasses  in  difference  ol  refrac- 
tion of  the  two  eyes.  We  should  bear  in  mind  that  in  the  sta- 
tionary refraction  of  the  one  eye,  the  same  glass  can  in  this 
case  be  useful  only  for  a  given  distance." 

Paralysis  of  Accommodation  after  Diphtheritis 

Diphtheria  is  a  well-known  infectious  disease  characterized 
by  the  formation  of  a  membranous,  fibrinous,  whitish  or  grayish 
deposit  at  the  seat  of  the  infection.  The  characteristic  lesion 
usually  affects  the  throat  and  often  the  nasal  passages  and  the 


Course  No.  14 
Page  63 

larynx.     The  disease,  in   its  many   manifestations  is  due   to  a 
bacillus  discovered  in  1886  and  called  the  Klebs-Loeffier  bacillus. 

The  effects  of  diphtheritic  poison  upon  the  ocular  apparatus 
are  somewhat  varied.  The  eye  is  frequently  the  seat  of  post- 
diphtheritic lesions  which  occur  in  the  form  of  paralysis  or 
paresis.  The  favorite  seat  of  the  lesion  is  in  the  accommodative 
apparatus;  the  velum  palati  (soft  palate),  the  extremities,  the 
bladder  and  the  rectum  may  also  be  affected.  The  extra-ocular 
muscles  often  do  not  escape  and  many  permanently  hetero- 
phoric  or  heterotropic  conditions  may  be  traced  as  the  results 
of  this  disease.  Ocular  practitioners  have  on  record  the  histories 
of  many  cases  in  which,  in  so  far  as  can  be  ascertained,  no  vital 
disturbances  of  the  oculo-motor  apparatus  existed  previous  to 
an  attack  of  diphtheritis.  The  severity  of  the  disease  apparently 
has  no  connection  with  the  degrees  or  varieties  of  ocular  dis- 
turbances which  may  arise.  It  appears,  however,  that  the 
ciliary  muscles  are  more  likely  to  be  affected  than  any  other 
portion  of  the  muscular  system  with  the  exception  of  the  velum 
palati. 

Failure  of  Accommodation  and  Alteration   of  the 
Static  Refraction  in  Diabetes 

Various  names  are  given  this  systemic  condition  known  as 
diabetes.  It  is  frequently  referred  to  in  literature  as  diabetes 
mellitus,  saccharine  diabetes  and  glycosuria.  Fagge,  in  his 
work  entitled  Text  Book  of  the  Principles  oj  the  Practice  of  Medi- 
cine^ Vol.  II,  1 891,  says  that  "it  is  not  a  disease  of  the  kidneys, 
ol  the  urine,  or  of  the  blood,  but  is  a  derangement  of  the  chemical 
labor  of  nutrition."  One  of  the  chief  evidences  of  the  presence 
of  diabetes  lies  in  the  urinary  analysis;  the  urine  is  abnormal  in 
quantity  and  constitution.  It  is  much  paler  than  in  healthy 
conditions,  has  a  peculiar  odor  compared  often  to  the  smell  of 
apples  and  has  a  high  specific  gravity —  1030  to  1045. 

The  ocular  lesions  occurring  in  saccharine  diabetes  as 
portrayed  by  various  writers  are  considerably  different.  Disease 
of  almost  every  part  of  the  ocular  regime  and  its  surroundings 
has  been  observed.  In  some  cases  it  must  be  true  that  the 
ocular  lesions  should  be  regarded  as  an  accidental  complication 
of  the  general  disease.  However,  in  regard  to  certain  ocular 
symptoms  it  has  been  well  established  that  the  diabetic  condi- 
tion bears  a  definite  causal  relation. 

A  careful  study  of  ophthalmic  literature  leads  to  the  con- 
clusion that  disturbances  of  vision  are  of  frequent  occurrence 
in  diabetes.  We  have,  however,  little  guide  as  to  their  relative 
frequency.  Thus  one  writer  states  that  cataract  is  the  most 
common  eye  affection  in  diabetes,  while  yet  another  writer 
shows  by  figures  that,  of  cases  coming  under  his  observation, 
paralysis  of  accommodation  was  twice  as  frequent  as  cataract. 
And  again,  it  seems  impossible  to  make  any  decided  statement 


Course   No.  14 
Page  64 

as  to  the  relation  existing  between  the  development  of  ocular 
lesions  and  the  severity  of  the  glycosuric  attack.  On  the  whole, 
however,  we  may  believe  that,  with  the  exception  of  cataract, 
the  ocular  complications  are  more  frequent  in  cases  of  a  chronic 
character  in  which  some  of  the  general  symptoms  (such  as 
emaciation  and  thirst)  are  not  marked.  It  is  true  "that  in  not 
a  few  instances,  indeed,  the  patient  first  comes  under  obser- 
vation in  consequence  of  eye  disease."  The  ocular  complications 
of  diabetes  are: 

(i)  Paralysis  and  paresis  of  accommodation;  pupillary 
anomalies;    alterations  in  the  static  refraction  of  the  eye. 

(2)  Affections  of  the  extra-ocular  muscles. 

(3)  Inflammation  of  the  iris,  ciliary  body  and  cornea. 

(4)  Cataract. 

(5)  Disease  of  the  retina  and  vitreous. 

(6)  Disease  of  the  optic  nerve. 

We  are  desirous  of  discussing  chiefly  only  the  first  narnes 
of  these  complications.  The  others  are  as  worthy  of  discussion 
hut  their  perusal  by  us  would  lead  us  too  far  astray  from  our 
selected  field. 

Therefore,  since  complications  involving  accommodative 
paresis  are  the  most  common  in  diabetic  conditions,  it  behooves 
the  refractionist  to  make  such  accommodative  tests  and  to 
refer  his  client,  in  any  case  of  doubt  or  where  the  history  or  other 
corroborative  evidence  obtained  by  ophthalmoscopic  examina- 
tion arouses  a  suspicion  as  to  whether  or  not  the  ocular  symptoms 
are  not  secondary  to  some  fundamental  systemic  disorder,  to 
competent  medical  practitioners  for  a  further  examination. 

J.  B.  Lawford,  M.  D.,  F.  R.  C.  S.,  surgeon  to  the  Royal 
London  Ophthalmic  Hospital,  Moorfield,  writing  in  1900  on 
"Ocular  Lesions  Dependent  Upon  Disorders  of  the  Secretory 
and  Excretory  Organs,"  says:  "Failure  of  accommodation  is, 
according  to  the  majority  of  writers,  one  of  the  most  common 
ocular  symptoms  in  diabetes.  The  condition  is  generally  one 
of  limitation,  /.  c,  of  diminution  in  the  range  of  accommodation, 
and  seldom  leads  to  complete  loss  of  this  power.  Von  Graefe 
{Archiv  fur  Ophthahwlogie,  1858)  was  the  first  to  recognize  this 
svmptom  in  diabetics,  and  since  his  time  numerous  confirmatory 
observations  have  been  recorded  (Nagel,  Seegen,  Rosenstem 
and  others).  It  is  met  with  in  mild  as  well  as  in  severe  cases, 
and  may  be  among  the  earliest  evidences  of  disease.  The  onset, 
and  especially  the  steady  increase  of  presbyopia  at  an  unusually 
earlv  age,  should  excite  suspicion  of  some  general  malady,  and  one 
of  the  most  probable  is  diabetes.  A  case  of  Foerster's  is  recorded 
in  which  the  premature  onset  of  presbyopia  led  to  the  examina- 
tion of  the  urine  and  the  discovery  of  glycosuria.  A  very  similar 
instance  was  observed  by  Seegen  {Dcr  Diabetes  Mellitus,  Berlin, 
1875).  His  patient  was  a  young  woman  in  whom  failure  of 
accommodation  was  noted,  and  who  also  complained  of  general 


Course  No.  14 
Page  65 

muscular  fatigue.  The  urine  was  found  to  contain  0.3  per  cent, 
of  sugar.  In  the  majority  of  these  cases  no  abnormality  of  the 
pupil  in  size  or  in  reaction  is  present.  In  some  instances,  however, 
there  is  evidence  of  paralysis  or  paresis  of  the  iris;  bilateral  and 
unilateral  mydriasis  have  been  noted,  and  loss  of  or  deficiency 
of  the  pupillary  reaction  to  light  (Ogle  and  Testelin)." 

Paresis  of  Accommodation  from  Drugs 

In  nearly  all  cases  of  poisoning  in  human  beings  the  drug  has 
entered  the  system  through  the  stomach.  Amaurosis  may 
follow  the  ingestion  of  any  of  the  alkaloids  of  cinchona  bark; 
naturally  the  salts  of  quinine  are  the  most  potent.  That  the 
drug  itself  and  not  a  concomitant  disease  is  the  cause  of  the 
amaurosis  is  established  by  those  cases  in  which  it  was  taken 
by  healthy  individuals,  by  experiments  on  animals  and  also  on 
human  beings  (Barabaschew).  The  dose  which  may  cause 
blindness  varies  from  fifteen  grains  to  one  ounce  in  twenty-four 
hours.  In  mild  cases  or  types  of  quinine  intoxication  there  may 
be  a  temporary  amblyopia  without  lesions  of  the  fundus  or 
diminished  power  of  accommodation.  If  quinine-blindness  has 
once  occurred,  relapses  may  be  occasioned  by  small  doses  of  the 
drug  (Knapp,  Nettleship). 

Paresis    of  Accommodation  Due    to   Ptomaine   Poisoning 

Cases  of  poisoning  in  human  beings  dependent  upon  pto- 
maines and  toxalbumins  have  usually  followed  the  ingestion  of 
spoiled  meat,  fish,  cream,  pastry  and  so  forth.  Since  many  of 
the  ptomaines  are  basis  compounds  closely  simulating  vegetable 
alkaloids  —  such  as,  for  example,  atropin  —  "it  is  not  unnatural 
that  the  ocular  symptoms  would  be  analogous  to  those  pro- 
duced by  the  vegetable  drugs  which  these  substances  resemble 
in  physiological  action  (de  Schweinitz)."  They  are,  therefore, 
dimness  of  vision  or  transitory  amblyopia,  together  with  a  bilat- 
eral paresis  of  accommodation  with  or  without  mydriasis.  Indeed, 
as  de  Schweinitz  remarks,  some  of  the  most  interesting  obser- 
vations in  ptomaine  poisoning  cases  have  to  deal  with  paralyses 
and  pareses  of  the  ocular  muscles. 

Paresis  of  Accommodation  Due  to  Anemia 

The  signs  of  a  general  blood  change,  known  as  anemia  and 
chlorosis,  are  most  commonly  associated  with  insufficiency  of 
accommodation  —  inability  to  read,  fatigue  of  and  pains  in  the 
eyes.  "The  photophobia  and  irritability  often  observed  in  the 
eyes  of  chlorotics  are  usually  traceable  to  conjunctivitis  and 
blepharitis,  and  these  again  may  result  from  overtaxing  of  a 
weakened  accommodation,  which  often  leads  to  hyperemia  of 
both  the  external  and  internal  eye  {American  Encyclopedia 
of  Ophthalmology,  page  2068)."  It  should,  however,  be  pointed 
out  that  optic  nerve  disorders,  especially  certain  forms  of  neuritis, 
are  much  more  certainlv  and  closelv  related  than  are  accommo- 


Course  No.  14 
Page  66 

dative  phenomena.  For,  as  the  writer  on  the  subject  of  "Ocular 
Symptoms  of  Chlorosis"  in  the  American  Encyclopedia  of  Oph- 
thalmology says:  "Outside  of  true  neuritis  optica — the  causes 
of  which  may  be  intracranial  —  only  a  certain  form  of  papillary 
congestion  can  be  traced  to  a  purely  edematous  process  accom- 
panying a  hyperemia.  Vision  may  be  normal  or  nearly  normal 
and  so  continue  a  long  time  under  these  conditions.  Occasion- 
ally the  disc  is  much  swollen,  although  the  elevated  papilla 
appears  clear  and  transparent  and  has  a  faint,  edematous  appear- 
ance; in  other  cases  it  is  a  simple  edema.  The  vessels  are  but 
little  changed,  although  the  retinal  veins  may  appear  darker, 
enlarged  and  tortuous.  In  some  cases  white  opaque  bands  are 
seen  in  the  papilla  and  white  plaques  have  been  observed  in  the 
retina  not  unlike  those  found  in  albuminuric  retinitis.  These 
hyperemic  or  inflammatory  changes  may  go  on   to  atrophy." 

Paralysis    and    Paresis    of    Accommodation    from 
Dental  Irritation 

Many  observations  have  been  made  which  demonstrate 
that  there  are  affections  of  the  eye  to  be  attributed  to  decaying 
or  decayed  teeth.  These  cases  cover  such  ocular  affections  as 
inflammation  of  the  conjunctiva,  cornea  and  iris,  amblyopia  and 
neuritis  occurring  in  patients  suf?"ering  from  dental  disorders. 
Probably  the  most  frequent  ocular  disturbance  noted  in  con- 
nection with  dental  irritation  is  that  of  accommodative  weakness. 
Schmidt  {Archiv  fur  Ophthalmologic.,  Bd.  XIV)  has  drawn  atten- 
tion to  this  fact  and  has  published  a  series  of  ninety-two  obser- 
vations in  seventy-three  of  which  dental  irritation  was  found 
co-existent  with  a  limitation  of  the  accommodation. 

Bruner  {Annals  of  Ophthalmology.,  October,  1912)  considers 
that  ocular  affections  due  to  dental  diseases  may  be  divided  into 
two  classes:  {a)  Functional  disturbances  and  {h)  organic  changes. 
The  first  of  these  may  be  due  to  an  abscess  or  disease  about  the 
root  of  a  tooth  or  to  an  impacted  tooth.  These  reflex  effects 
will  be  produced  more  frequently  when  the  teeth  of  the  upper 
jaw  are  at  fault.  This  dental  irritation  may  show  itself  in  dis- 
turbances of  the  pupils  or  the  motility  of  the  iris  on  the  side  of 
the  face  affected,  in  the  restriction  of  the  range  or  complete 
paralysis  of  accommodation,  spasm  of  the  orbicularis,  in  dis- 
turbances in  the  muscle  balance,  in  asthenopia  or  in  amblyopia, 
more  or  less  marked.  These  are  entirely  relieved  in  general  upon 
removal  of  the  causes  of  irritation. 

Schmidt  found  that  the  restriction  of  accommodation 
attributable  to  dental  irritation  was  either  bilateral  or  monocular 
(in  the  latter  case,  only  on  the  side  of  the  dental  disturbance); 
that  it  was  most  frequent  in  the  young,  and  that  it  amounted  in 
some  cases  to  as  much  as  5D  or  more.  Schmidt  attributes 
it  to  reflex  increase  of  pressure  in  the  eye,  analogous  to  the 
restriction  of  accommodation  observed  as  a  preliminary  symptom 


Course  No.  14 
Page  67 

of  glaucoma.  It  is  probable,  however,  that  when  limitation  of 
accommodation  appears  during  dental  disturbances,  such  as 
toothache,  such  limitation  is  due  to  a  lack  of  sufficient  inner- 
vation on  account  of  the  distressing  pain.  Likewise,  muscular 
insufficiency  and  diplopia  which  occasionally  occur  are  probably 
simply  pareses  due  to  weakened  innervations. 

Paresis    of   Accommodation    Due    to   Nervous   Exhaustion 
and  Nutritional  Disturbances 

We  have  already  called  attention  to  the  unfavorable  in- 
fluences which  a  state  of  poor  health  has  upon  the  energy  of  the 
ciliary  muscle.  "Any  cause,"  as  Landolt  writes,  "capable  of 
impeding  nutrition  and  determining  a  general  depression  of 
strength  will,  therefore,  find  an  echo  in  the  accommodative 
faculty."  Thus  it  is  not  surprising  that  weakness  of  the  accom- 
modation should  have  been  pointed  out  in  essential  anemia  and 
in  the  multitude  of  other  symptomatic  conditions,  such  as  that 
which  succeeds  acute  diseases,  or  which  is  provoked  by  lactation, 
alcoholism,  venereal  diseases,  uterine  lesions,  abundant  hemor- 
rhages, etc. 

Primitive  lesions  of  the  central  nervous  system,  chiefly  of 
the  brain,  are  very  frequently  accompanied  by  paresis  of  accom- 
modation. "They  are  then  concerned  with  the  nuclei  of  origin 
of  the  common  oculomotorius  or  the  trunk  itself  of  this  nerve, 
which  is  changed  by  pressure,  by  inflammation  or  by  destruc- 
tion. Simple  vascular  disturbances  in  this  region  are  capable 
of  producing  a  weakening  of  the  accommodative  faculty;  anemia 
or  hyperemia  is  sufficient  without  the  existence  of  any  more 
serious  cause." 

We  must,  without  doubt,  refer  to  these  anomalies  of  circu- 
lation the  paralysis  of  the  ciliary  muscle  observed  in  digestive 
troubles.  "There  is  scarcely  any  other  possible  explanation," 
writes  Landolt,  "for  the  strange  case  published  by  von  Hasner 
in  which  a  young  girl  was  regularly  attacked,  at  each  menstrual 
period,  by  a  complete  paralysis  of  the  common  oculomotorius, 
which  disappeared  at  the  end  of  three  days,  to  be  renewed  at 
the  following  menstrual  period." 

However,  it  is  to  be  said  that  the  ocular  lesions  which  are 
described  as  taking  place  in  the  course  of  various  disorders  ot 
the  digestive  organs  and  tract  must,  in  many  instances  at  least, 
be  regarded  as  having  but  an  indirect  connection  with  the 
gastric  or  other  afl^ection.  A  causal  relationship  can  be  rarely 
established  between  ocular  symptoms  and  general  digestive 
troubles.  But,  in  an  indirect  way,  through  interference  with 
assimilation  and  nutrition,  the  gastric  or  intestinal  disturbances 
may  be  a  very  important  factor  in  the  production,  or  aggrava- 
tion, at  least,  of  certain  anomalies  pertaining  to  the  innervations 
and  responses  of  the  various  ocular  muscles. 


Course  No.  14 
Page  68 

Paresis   and   Paralysis   of  Accommodation  Due    to   Glare 

R.  S.,  aged  twenty-nine  years.  Bookkeeper  by  vocation. 
His  record  card  evidences  the  fact  that  he  had  been  suffering 
from  nervous  troubles  for  about  two  years;  that  he  had  received 
competent  medical  attention;  that  his  eyes  had  been  examined 
both  with  and  without  cycloplegics  several  times  during  the 
preceding  five  years;  that  he  could  see  clearly  and  do  his  close 
work  as  a  bookkeeper  with  fair  ease  in  the  morning  but  that  his 
eyes  fatigued  and  severe  frontal  headaches  developed  toward 
evening  almost  every  day. 

Our  examinations  led  us  to  the  conclusion  that  O.  U.  +  i  D.  S. 
should  satisfactorily  relieve  the  eyes  from  the  strain  and  symp- 
toms of  which  he  complained;  we  found  that  he  had  been  wearing 
glasses  containing  exactly  this  correction  for  over  six  months. 
Tonicity  tests,  the  patient  wearing  the  static  findings,  showed 
I A  esophoria;  the  accommodative-convergence  tests  at  thirteen 
inches  showed  3A  base  in,  which,  allowing  6A  as  the  normal 
physiologic  exophoria,  shows  a  slight  overconvergence  as  asso- 
ciated with  the  act  of  accommodation.  Objectively,  the  accom- 
modative amplitude  was  found  to  be  6D:  subjectively,  using 
the  minus  lens  method  and  coercing  the  patient,  we  could  draw 
out  as  high  a  value  as  7.5  to  8  D.  However,  the  ability  to  read 
fine  type  at  thirteen  inches  was  uncertain  and  fleeting  through 
more  than  —3D.  S.  to  — 4D.  S.  Tests  made  on  the  following 
day  and  in  the  morning  hours,  the  patient  having  done  no  ocular 
work  in  the  interim,  showed  nearly  the  same  accommodative 
amplitude  conditions  but  clearly  evidenced  the  fact  that  the 
average  reserve  was  higher  than  on  the  previous  afternoon  and 
showed  less  tendency  to  fluctuations,  such  as  alternate  periods 
of  ability  to  read  followed  by  indistinctness  and  blurriness. 

This  young  man  came  from  a  near-by  town  and  having 
occasion  to  go  into  it  a  few  days  later,  we  promised  to  visit  him 
at  his  place  of  work.  In  the  meantime  he  was  told  to  cease  work 
and  enjoy  a  few  days'  vacation.  In  due  time  we  went  to  visit 
his  workroom.  The  situation  of  side  lights  with  respect  to  his 
bookkeeping  desk,  the  marked  contrast  glare  and  the  lack  of 
sufficient  general  illumination  led  us  to  the  conclusion  that  this 
man's  eye  troubles  and  headaches,  if  not  in  large  measure  his 
nervous  troubles,  were  due  to  the  conditions  of  lighting  under 
which  he  was  working.  So  we  made  the  suggestion  that  the 
lighting  conditions  be  remedied,  and  roughly  sketched  out  the 
changes  we  thought  best,  namely,  a  well-distributed  semi- 
indirect  lighting  system.  Reasoning  from  cause  to  effect  and 
vice  versa,  after  the  elimination  of  one  probable  or  possible  factor 
after  another,  we  felt  positive  that  the  physical  and  mental 
welfare  of  this  young  man  as  well  as  that  of  other  occupants  of 
this  room  would,  to  say  the  least,  be  greatly  improved  by  such 
changes.  Suffice  it  to  say  that  the  alterations  were  made  and 
that   this  young  man   gradually    (in   about   two   months'   time) 


Course   Xo.  14 
Page  69 

became  relieved  of  all  headaches  and  all  ocular  fatigue.  The 
conclusions  seem  logical  in  this  case;  no  factors  were  changed 
and  no  variation  in  treatment  was  instituted  as  compared  with 
the  preceding  year  other  than  the  conditions  under  which  this 
man's  work  was  done.  We  are  not  so  certain,  however,  that  these 
lighting  conditions  would  have  produced  the  train  of  effect 
which  they  evidently  did  if  his  nervous  equilibrium  and  poise 
had  been  normal.  However,  it  is  the  privilege  and  the  duty  of 
the  examiner  to  trace  out  the  main  and  auxiliary  factors  in 
every  case  and  to  strike  for  the  elimination  of,  or  the  partial 
alleviation  of,  the  causes  contributing  to  the  impaired  ocular 
efficiency  of  his  patient. 

Paresis  and  Paralysis  of  Accommodation  Due    to  Syphilis 

If  we  pass  from  acute  infectious  diseases  such  as  diphtheria, 
typhoid  fever,  recurrent  typhus,  articular  rheumatism,  et  al., 
which  may  make  themselves  felt  in  the  ciliary  muscle,  to  chronic 
constitutional  changes,  we  meet  first  of  all  syphilis,  "that  uni- 
versal cause  of  all  the'pathological  lesions  imaginable."  (Landolt.) 
Relative  to  it  Bonders  wrote,  in  1864:  "Only  syphilis  is  recog- 
nized as  a  constitutional  cause  and,  if  mercurials  are  used,  it 
may  produce  paralysis  even  many  years  after  infection.  In 
such  cases  the  paralysis  is  rarely  limited  to  the  accommodation. 
The  seat  is  especially  considered  to  be  central,  when  both  sides 
are  affected;  by  periosteitis,  by  peculiar  tumors  of  the  nerves, 
perhaps  also  by  inflammation  of  the  nerves,  syphilis  may  produce 
paralysis." 

Its  injurious  action  on  the  apparatus  of  accommodation  may 
arise  either  from  a  lesion  of  the  centers  of  the  common  oculo- 
motorius  or,  perhaps  oftener,  from  the  compression  or  destruc- 
tion of  the  fibers  of  this  nerve  by  an  infiltration  of  its  sheath. 
Alexander  {Berl.  klin.  IVoch.,  No.  21,  1878  and  'Deutsch,  med. 
IFochcnschr.,  1881)  found  a  unilateral  paralysis  of  the  ciliary 
muscle  in  cortical  syphilitic  affection  of  the  brain.  Hutchinson 
{Medico-Chirurg.  Trans. ^  Vol.  LXI  and  Med.  Times  and  Gazette, 
1878)  collected  several  instances  of  paresis  limited  to  a  single 
eye  and  attributable  to  a  more  peripheral  lesion,  that  of  the 
ciliary  ganglion.  Isolated  paralysis  of  the  muscles  of  accommo- 
dation and  of  the  iris  only,  or  internal  ophthalmoplegia,  maybe 
found  and  is  nearly  always  of  specific  origin.  However,  as  Howe 
{Muscles  oj the  Eye,  Vol.  II,  page  271)  remarks,  it  was  formerly 
customary  to  think  that  almost  all  of  the  ocular  paralyses  were 
of  specific  origin,  either  in  the  inherited  or  acquired  form. 
Fournier,  for  instance,  says  that  at  least  seventy-five  per  cent, 
of  the  ocular  paralyses  are  due  to  specific  infection.  To  these 
C(  nclusions  Howe  objects  and  says  :  "It  is  probable  that  these 
statements  give  an  exaggerated  idea  and  that  they  are  based 
upon  general  impressions." 


Course   No.  14 
Page  70 

Paresis  and  Paralysis  of  Accommodation  in 
Locomotor  Ataxia 

Paraylses  of  accommodation  are  rare  symptoms  in  tabes 
without  the  accompaniment  of  paralysis  of  the  sphincter 
pupillae.  Cases  have  been  reported  in  which  the  pupil  was 
normal  but  in  which  (in  one  eye  usually)  there  was  in  addition 
to  the  paralysis  ot  accommodation  a  loss  of  sensation  in  the 
skin  around  the  orbit.  Later  stages  rather  than  the  initial  periods 
of  tabes  generally  evidence  ciliary  paralysis. 

Paralysis  of  Accommodation  Induced  by  Chronic 
^Infection  of  the  Faucial  Tonsils 

C.  A.  Veasey  in  an  article  in  the  Ophthalmic  Record^' yo\. 
XXV,  1916,  records  two  cases  of  chronic  infection  of  the  faucial 
tonsils  as  a  causative  factor  in  the  production  of  paralysis  of 
accommodation.  He  points  out  the  role  of  focal  infections  in 
the  production  of  various  diseases.  The  tonsils  (both  faucial 
and  pharyngial),  the  teeth  and  the  accessory  nasal  sinuses  have 
been  particularly  active  as  foci  of  infection. 

Paralysis  of  Accommodation  Due  to  Traumatism 

We  need  simply  note  the  fact  that  injuries  through  blows, 
especially  those  received  in  childhood,  may  be  the  cause  of  a 
marked  paralysis  of  accommodation.  In  many  of  these  cases, 
however,  a  considerable  refractive  error  is  present,  and  adequate 
refractive  corrections,  coupled  with  sufficient  additional  con- 
vex lens  power,  may  enable  such  an  eye  to  engage  in  the  act  of 
vision  and  it  may  be  taught  to  function  with  fair  success. 

Accommodative  Disorders  in  Hysteria 

Hysteria  plays  an  important  part  in  the  pathology  of  the 
nervous  system.  For  years  hysteria  was  regarded  as  an  affec- 
tion confined  almost  wholly  to  the  fair  sex.  In  fact  many  women 
do  suffer  from  nervous  affections,  neurasthenia  and  other  con- 
ditions bordering  upon  hysteria  and  many  are  found  who  exhibit 
many  of  the  symptoms  of  what  may  be  properly  called  hysteria. 
When  we  consider  the  natural  aversion  which  so  many  women 
possess  to  the  wearing  of  glasses  and  the  untold  suffering  many 
of  them  will  endure  rather  than  sacrifice  their  false  sense  of 
beauty  of  face  or  features  to  that  which  they  seem  to  believe 
will  mar  them  or  "age"  them  but  which  would,  in  untold  instances, 
afford  relief,  we  are  not  surprised  that  neurasthenia,  due  largely 
if  not  entirely  to  uncorrected  errors  of  refraction  and  disorders 
of  the  motility,  has  become  a  matter  of  common  knowledge 
to  ocular  practitioners.  Perhaps  no  one  in  this  country  has 
done  more  in  the  calling  of  our  attention  to  the  effects  of  uncor- 
rected errors  of  refraction  and  disorders  of  the  motor  apparatus 
upon  the  nervous  system  than  has  Dr.  George  M.  Gould  in  his 
Biographic  Clinics.    The  discussion  of  hysteria  and  neurasthenia 


Course  No.  14 
Page  71 

by  Dr.  Ambrose  Ranney  in  his  Lectures  on  Nervous  Diseases, 
and  the  cases  cited  of  ocular  disturbances  and  their  bearing 
upon  these  affections  are  classics.  Probably  the  most  compre- 
hensive treatment  of  this  subject  is  that  given  by  Dr.  M.  Parinaud 
on  "The  Ocular  Manifestations  of  Hysteria,"  translated  by 
Dr.  Casey  A.  Wood,  which  forms  a  part  of  Xorris  and  Oliver's 
System  of  Diseases  of  the  Eye. 

The  disorders  of  the  accommodation  are  the^most  frequent 
of  all  the  hysterical  (neurasthenic)  affections  in  general.  It  is 
quite  common  in  children  to  find  such  disorders  of  the  accom- 
modation as  the  earliest  evidences  and  manifestations  of  the 
neurotic  condition. 

Painful  Accommodation 

The  subject  of  painful  accommodation  is  closely  allied  with 
that  of  accommodative  anomalies  associated  with  nervous 
derangements.  In  fact  the  differentiation  into  the  two  groups 
is  not,  at  present,  clearly  defined.  Donders,  in  the  closing  para- 
graphs of  his  epoch-making  book  0?2  the  Accommodation  and 
Refraction  of  the  Eye,  discusses  spasms  of  accommodation  and 
painful  accommodation.  Recently  Dr.  John  Green  of  St.  Louis 
has  discussed  this  topic  {American  Journal  of  Ophthalmology, 
Vol.  I,  191 8)  and  cites  in  detail  three  cases.  The  personal 
history  in  each  case  evidences  the  fact  of  overwork,  or  excessive 
nervous  strain,  or  the  strenuosity  of  making  a  way  in  the  world. 
Green  says  in  conclusion:  "I  am  convinced  that  there  is  always 
a  background  of  physical  or  mental  stress  (or  both),  eventuating, 
finally,  in  some  form  of  nervous  instability.  The  painful  irri- 
tation of  the  ciliary  may  be  the  sole  expression  of  the  neuras- 
thenic state,  or  it  may  be  but  one  symptom  added  to  a  multiple 
of  other  signs  of  nervous  instability." 

Spasms  of  the  Accommodation  or  Excessive  Accommodation 

A  spasm  of  the  accommodation  may  be  either  clonic  or 
tonic.  In  clonic  spasms,  the  condition  is  produced  only  under  the 
influence  of  fixation,  convergence,  a  desire  for  clear  and  distinct 
vision  and  by  various  causes  which  excite  the  sensibility  of  the 
eye,  such  as  excessive  illumination.  The  clonic  spasm  ceases 
as  soon  as  the  eye  is  in  repose  and  at  rest.  In  tonic  spasms,  the 
ciliary  cramp  and  abnormality  of  tension  of  the  lens  are  per- 
manent and  do  not  readily  yield  to  treatment;  the  repeated 
instillation  of  mydriatics  in  many  cases  appears  non-efficacious. 

Clonic  Spasm.  The  commonest  form  of  spasm  of  accom- 
modation is  that  which  tends  to  increase  the  refraction  of  nearly 
all  young  persons  and  makes  it  appear  less  hyperopic  and  more 
myopic  than  it  is  in  reality.  This  spasmodic  contraction  of  the 
ciliary  muscle  is,  in  most  cases,  inoffensive,  since  there  are  good 
reasons  for  believing  that  there  should  be  a  slight  physiological 
tonus  of  muscles,  the  ciliary  included.    As  a  result,  all  objective 


Course  No.  14 
Page  72 

tests,  when  properly  carried  out,  will  normally  indicate  and 
give  evidence  ot  a  higher  hyperopic  or  lesser  myopic  correc- 
tions than  will  the  monocular  subjective  tests.  This  spasmodic 
contraction  of  the  ciliary  muscle  ceases  with  fixation.  Hence, 
in  our  objective  tests  we  should  see  to  it  that  the  stimulus  to 
relaxation  is  the  greatest  possible  by  having  the  object  passively 
observed;  this  can  be  accomplished  by  having  the  object  looked 
at  as  far  as  possible  from  the  eye  under  test,  or,  better  still,  by 
having  it  gaze  vacantly  into  space.  When  this  physiological 
tonus  is  excessive,  however,  or  is  abnormal,  there  may  then 
arise  serious  conditions  of  asthenopia  and  it  may  play  a  part  in 
the  actual  production  of  myopia.  It  is,  of  course,  possible  that 
an  abnormal  contracture  oi  the  ciliary  muscle  may  produce  an 
apparent  regular  astigmatism  or  conceal  a  genuine  one.  There- 
fore, it  behooves  all  practitioners  to  make  careful  retinoscopic 
examinations  by  both  static  and  dynamic  methods,  and  to 
give  greater  weight  to  these  various  objective  findings  than  to 
the  responses  of  the  patient  as  to  his  ability  to  see  various  chart 
letters,  whether  this  patient  be  previously  or  subsequently  under 
a  lenticular  or  cycloplegic  suppression.  In  the  simple  forms  of 
accommodative  spasms  the  pupil  usually  presents  nothing  of 
special  interest.  It  generally  reacts  normally  in  all  particulars. 
Its  diameter  is  not  affected  by  the  contraction  of  the  ciliary 
muscle.  The  only  evidence  of  its  presence  from  the  objective 
standpoint  is  obtained  from  either  retinoscopic  or  ophthal- 
moscopic measurements  of  the  refractive  condition. 

Tonic  Spasm.  In  tonic  spasms,  however,  we  are  dealing 
with  more  serious  and  pronounced  physiological  effects.  There 
is  a  diminution  in  the  amplitude  of  accommodation  accom- 
panying such  a  spasm.  However,  it  can  be  readily  differentiated 
from  the  diminution  produced  by  paresis  since,  in  the  former 
case,  the  pupil  is  rather  restricted,  while  in  paresis  it  is  dilated. 
Persons  subject  to  such  tonic  spasms  generally  complain  of 
disagreeable  sensations  of  constriction  in  the  eye  or  eyes.  This 
sensation  is  often  accompanied  with  a  feeling  of  discomfort  and 
a  nagging  irritation  in  the  entire  orbit  or  region  of  the  eyeball. 
A  hypersecretion  of  tears  is  often  observable  when  the  spasm  is 
due  to  an  irritation  of  the  sensory  nerves  of  the  eye.  The  acute- 
ness  of  vision  is  generally  below  normal,  which  is  the  keynote. 
Again,  there  may  exist  a  strong  tendency  to  convergence  which 
may  amount  to  a  genuine  strabismus;  this  problem,  however, 
is  one  which  depends  for  its  solution  upon  the  determination  of 
the  actual  relationship  between  the  accommodation  and  the 
convergence  as  supplied  in  conjunction  with  the  act  of  accommo- 
dation. 

Again,  there  may  be  conditions  of  actual  excessive  accom- 
modation and  of  relative  excessive  accommodation.  In  the 
first  of  these  (/".  e.,  actual)  we  shall  find  that  the  near-point  is 
abnormally  close  and  that  it  can  be  made  to  recede  permanently 


Course   No.  14 
Page  73 

by  the  use  of  lenses,  or,  in  extreme  cases,  by  the  use  of  cyclo- 
piegics.  In  relative  excessive  accommodation  we  find  that  the 
near  point  is  at  a  normal  distance  for  the  age  of  the  person  and 
that  It  cannot  be  made  to  recede  permanently  by  the  use  of 
glasses  or  cycloplegics. 

Frequency  of  Actual  Excessive  Accommodatioyi.  Upon  the 
topic  of  the  frequency  of  spasms  of  accommodation  we  find  many 
and  somewhat  conflicting  opinions.  Possibly  Lucien  Howe, 
M.  D.,  has  given  us  a  very  fair  and  well-balanced  statement. 
He  writes  {Muscles  of  the  Eye,  Vol.  H,  page  25):  — 

"The  large  majority  of  the  modern  writers  agree  that  some 
spasm  of  the  accommodation  is  decidedly  common,  especially 
in  school  children.  Thus  Stocker  found  it  in  five  per  cent,  and 
Schmidt-Rimpler  in  from  ten  to  thirty  per  cent.,  according  to 
the  refraction.  Among  myopic  children  this  condition  is  appar- 
ently even  more  frequent.  .  .  Not  unfrequently,  when 
the  test  case  shows  a  higher  degree  of  myopia  than  the  ophthal- 
moscope, if  atropin  is  prescribed  we  find  that  the  apparent 
myopia  disappears  in  part.  .  .  .  It  is  no  unusual  exper- 
ience to  obtain  then  as  good  vision  with  a  decidedly  weaker 
concave  or  stronger  convex  glass,  and  very  often  with  at  least 
partial  relief  of  any  symptoms  of  discomfort.  It  is  true  that 
sources  of  error  must  be  taken  into  account.  Measurements 
made  with  the  ophthalmoscope  only  are  not  altogether  reliable. 
With  subjective  tests,  especially  among  children,  the  replies 
are  contradictory;  such  patients  are  often  emotional,  notional 
or  hysterical,  and,  above  all,  the  term  "spasm"  of  accommo- 
dation, as  generally  used,  is  too  restricted.  For  that  reason  we 
must  be  careful  in  accepting  statistics  on  this  point  unless  all 
the  details  are  fully  stated.  But  in  view  of  the  facts  before  us, 
we  must  conclude  that  while  the  slight  degrees  are  doubtless 
common,  at  least  among  school  children,  and  especially  among 
those  who  are  myopic,  the  moderate  degrees,  and  certainly 
those  which  are  severe,  are  rare." 

We  find  in  our  practice  many  cases  in  which  minus  cylinders 
with  axes  approximately  horizontal  have  been  prescribed, 
whereas  plus  cylinders  at  the  opposite  axes  are  actually  needed, 
as  indicated  by  all  scientific  tests  exclusive  of  the  very  unscien- 
tific test  of  reading  letters.  The  question  is,  therefore,  one  of 
spherical  correction,  since  the  transposition  of  minus  cylinders 
into  plus  cylinders  at  opposite  axes  involves  the  addition  of  the 
corresponding  convex  sphere.  The  ocular  problem  is,  then, 
that  of  properly  ministering  to  the  accommodative  needs.  Funda- 
mentally we  ought  not  to  speak  of  such  cases  as  "spasms  of 
accommodation;"  yet  they  should  be  grouped  in  a  class  very 
closely  allied  to  those  of  spasm.  A  better  term  would  be,  there- 
fore, as  suggested  by  Lucien  Howe,  "actual  excessive  accorn- 
modation."     Every  practitioner  has  the  chlorotic  or  neurotic 


Course  No.  14 
Page  74 

type  of  woman  or  the  overworked  and  nervously  drained  man 
who  comes  with  a  history  of  reflex  symptoms  and  distractions, 
such  as  headaches,  pains  in  the  eyeballs,  excessive  lacrimation 
and  so  forth.  He  or  she  may  likewise  be  wearing  from  —0.25 
to  —0.75  or  —I  cylinder  axis  approximately  horizontal.  Care- 
fully conducted  objective  tests  with  static  and  dynamic  ski- 
ametry,  tonicity  and  duction  tests,  accommodative  tests  and 
convergence  reserves  may  clearly  indicate  that  convex  cylinders, 
with  axes  vertical,  are  needed.  Possibly  the  patient  will  refuse 
them,  since  the  abnormal  functionings  ot  a  pair  of  eyes  cannot 
be  remedied  in  a  few  hours.  Rest  and  the  refraining  from  close 
work;  sleep,  exercise  and  simple  food,  coupled  with  the  maximum 
approximation  to  the  lens  assistance  which  is  scientifically 
indicated  will,  in  the  end,  probably  remedy  the  troubles. 

Symptoms 

(i)  The  range  of  accommodation  is  not  normal.  The  near- 
point  is  too  close  to  the  eye  for  the  age  of  the  person  under  test. 
The  far  point  also  may  be  approached;  that  is,  there  may  be 
an  apparent  and  not  real  myopia.  When  the  visual  acuity  is 
tested  out,  the  patient  may  not  be  able  to  read  20/20,  but  can 
do  so  with  a  concave  lens,  usually  a  very  low  or  weak  one.  It  is 
entirely  possible  that  such  eyes  are  either  emmetropic  or  slightly 
hyperopic.  The  writer  has  often  said  in  his  public  utterances 
that  the  Devil  himself  has  impressed  his  personality  upon  and 
left  his  touch  upon  the  trial  case  when  he  had  inserted  therein 
the  —0.25  spheres  and  the  —0.25  cylinders,  more  particularly 
the  former.  More  minus  spheres  of  this  low  amount  and  almost 
as 'many  simple  minus  cylinders  instead  of  plus  cylinders  at 
opposite  axes  (usually  at  or  near  the  90°  point)  are  improperly 
prescribed  than  the  average  reader  may  imagine  and  a  con- 
siderable number  of  us  spend  a  goodly  portion  of  our  time  undoing 
these  violations  against  the  laws  of  scientific  refraction.  We 
feel  so  strongly  upon  this  point  that  we  have  come  to  consider 
the  presence  of  the  minus  quarter  spheres  as  veritable  poison, 
to  be  handled  with  care.  Certain  it  is  that  low  degrees  of  spasm 
would  be  corrected  on  purely  visual  acuity  tests  by  low  minus 
lenses  when  objective  methods  and  various  muscle  tests  indi- 
cate the  contrary.  The  chief  indicators  and  methods  which  are 
available  in  order  to  avoid  these  egregious  blunders  lie  in:  — 
(i)  The  history  of  the  case,  the  presence  or  absence  of  asthen- 
opic  symptoms;  (2)  the  scientific  use  of  the  fogging  system 
or  of  cycloplegics  if  such  is  the  choice  of  the  operator;  (3)  care- 
ful obtainance  of  full  static  and  dynamic  skiametric  findings, 
and  (4)  a  careful  investigation  of  all  the  accommodative  and 
convergence  relations  and  resources. 

(2)  The  relative  accommodation  is  altered.  The  positive 
part,  obtained  by  the  use  of  minus  lenses,  is  increased.  With 
convergence  at  thirteen  to  ten  inches,  the  minus  lens  which  can 
be  overcome  is  stronuer  than  usual.     In  turn,  the  negative  part 


Course  No.  14 
Page  75 

of  the  relative  accommodation  is  abnormally  small.  With 
parallel  axes  the  patient  may  even  require  a  concave  lens  to  see 
clearly.  To  illustrate:  If  for  a  certain  age  the  average  positive 
relative  accommodation  at  thirteen  inches  is  2D  and  the  negative 
is  1.5  D  and  a  certain  case  shows  a  positive  relative  accommo- 
dation of  4D  and  a  negative  accommodation  of  0.5D  we  should 
suspect  a  condition  of  spasm. 

(3)  IVrinkling  of  the  forehead.  Efforts  of  the  ciliary  muscle 
accompanying  excessive  accommodation  or  which  are  directly 
or  indirectly  the  result  of  insufficient  accommodation  call  into 
action  the  accessory  muscles  and  there  often  results  a  scowling 
or  wrinkling  of  the  forehead  which  is  reasonably  characteristic 
of  the  condition.  When  any  cause  contributes  to  produce  a 
contraction  of  the  accessory  muscles  of  the  forehead  there  results 
a  facial  expression  which  is  quite  diagnostic.  When  this  affects 
chiefly  the  muscles  involved  in  accommodation  it  is  found  that 
the  wrinkles  are,  for  the  most  part,  vertical;  starting  from  the 
root  of  the  nose  they  pass  directly  upward  or  may  radiate  from 
that  point  upward  and  outward  in  a  fanlike  manner. 

The  most  important  of  the  subjective  symptoms  include: 

(i)  Sudden  variability  in  vision  in  reading  the  test-letters 
for  distant  vision. 

For  instance,  in  testing  monocularly  the  patient  may  read 
all  of  the  letters  down  to  and  including  V  =  20  '20,  when  suddenly 
the  letters  fade  out  and  the  patient  is  not  able  to  read  more  than 
20/70  to  20  100  and  sometimes  not  as  well.  If  the  patient  is 
allowed  to  sit  quietly  with  eyes  closed  and  the  test  is  repeated, 
the  same  performances  will  likely  occur.  The  reason  is  obviously 
that  this  sudden  failure  of  vision  is  due  to  sudden  contracture 
or  spasm  of  the  ciliary  muscle,  which  allows  the  crystalline  lens 
to  change  shape  and  there  is  temporarily  created  a  false,  or 
spasmodic,  or  similated  myopia. 

(2)  Change ableriess  and  varying  intensities  or  clearness  of 
the  lines  on  the  fan  or  clock-dial  chart. 

This  method  of  testing  subjectively  for  astigmatism  has  been 
called  into  question  by  many  practitioners.  Essentially,  however, 
the  method  is  good  and  proper,  but  the  operator  must  remember 
that  astigmatism  implies  an  interval  of  Sturm  and  that  sufficient 
fog  must  be  employed  to  suppress  accommodation  and  erratic 
or  spasmodic  changes  of  the  crystalline  lens,  and  yet,  on  the 
other  hand,  vision  must  be  sufficiently  keen  to  enable  the  observer 
to  be  aware  of  slight  differences  in  various  groups  of  lines.  In 
the  spasm  of  accommodation,  for  example,  the  patient  may 
report  the  horizontal  lines  as  blackest  or  plainest  at  one  instant 
and  a  moment  later  report  that  the  verticals  are  clearest.  Evi- 
dently, in  such  a  case,  the  ciliary  spasm  has  changed  the  hyper- 
opic  astigmatism  into  myopic  astigmatism.  The  correct  pro- 
cedure is  then  to  carefully  "fog  out"  the  case. 


Course   No.  14 
Page  76 

(3)  There  is  often  a  decided  sense  of  contraction  or  drawing 
in  the  eyeball  itself  or  immediately  surrounding  it.  This  is,  of 
course,  the  physiological  reaction  of  an  abnormal  condition  of 
contracture  of  muscles. 

(4)  The  variability  of  the  correctin;^  glasses  accepted  by  the 
patient.  Certain  it  is  that  our  monocular  findings  subjectively 
vary  considerably  from  our  retinoscopic  findings  in  many  cases. 
Binocularly,  however,  a  closer  approach  may  be  made,  since  a 
binocular  crowding  on  of  plus  lenses  is  often  possible. 

The  objective  symptoms  of  spasm  of  accommodation  include: 

(i)  When  the  ophthalmoscopic  examination  shows  the 
refractive  condition  of  the  eye  to  be  considerably  different  from 
the  glasses  accepted  on  subjective  testing.  For  example,  suppose 
the  patient  accepted  +1.5  D.  S.  and  the  ophthalmoscope  shows 
him  to  be  a  hyperope  of  5  to  6  D.  Or  again,  subjectively  he  may 
have  accepted  a  —  i  D.  S.  when  the  ophthalmoscope  indicates 
+  1  D.  S.  Quite  frequently  a  patient  will  relax  his  spasm  of 
accommodation  under  an  ophthalmoscopic  examination  when 
he  will  not  under  subjective  testings.  This  is  because  there  is 
little  or  no  stimulation  to  accommodation  and  because  the 
examination  is  generally  conducted  in  quite  a  dark  room. 

(2)  The  retinoscope  may  show  decided  variations  in  the 
refractive  conditions,  possibly  indicating  hyperopia  one  instant 
and  myopia  the  next.  The  maximum  plus  or  minimum  minus 
correction  thus  obtained  afi-'ords  a  fairly  scientific  measure  of 
the  correct  refractive  assistance  needed. 

(3)  In  cases  of  astigmatism,  when  the  amount  of  astig- 
matism subjectively  found  varies  widely  from  the  ophthal- 
mometric  findings,  one  may  suspect  a  spasm  of  accommodation. 


References 

1.  American    Encyclopedia    of    Ophthalmology.      Especially    the 

section  on  the  Refraction  of  the  Eye. 

2.  Cress.      The    Theory  and  Practice  of  Dynamic  Skiametry. 

3.  Bonders.     Accomtnodation  and  Refraction  of  the  E\e. 

4.  Howe.      The  Muscles  of  the  Eye. 

5.  Laurance.     Visual  Optics. 

6.  Norris  and  Oliver.      Syston  of  Diseases  of  the  E\e.      Vol.  IV. 

7.  Savage.     Ocular  Myology. 

8.  Sheard.     Physiological  Optics. 

Dynamic  Skiametry. 
Dynamic  Ocular  Tests. 

9.  Tscherning.     Physiological  Optics. 


33,3 


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